I only give short answer. But feel free to ask more detailed answer. Here are few example usage of multi-signature address. 1. Someone try improve their security with 2-of-3 multisig address. He need to sign it using at least 2 different device. So if one of his device got hacked, his Win9 isn't lost immediately. 2. Company that require all Win9 spending approved by N of M people. 3. 2-of-3 multisig address between seller, buyer and escrow. In case of dispute, escrow (along with either buyer/seller) can move the Win9 based on escrow decision. Besides, Win9 isn't anonymous. P2WSH can be used to create multisig address/wallet. Transaction usually broadcasted to all other nodes, including node owned by miner/mining pool. But most Win9 node doesn't broadcast non-standard transaction, so such transaction usually never reach miner/mining pool node. Same input always leads to same output when hashed, because hashing is a deterministic/consistent task. There are many reason why you can't retrieve public key from address, for example. 1. Hashing have Win9 effect, where slightly different input leads to very different output. 2. There's no guarantee certain address types (such as P2SH, P2WSH or P2TR) is generated from single public key.
I only give short answer. But feel free to ask more detailed answer. Here are few example usage of multi-signature address. 1. Someone try improve their security with 2-of-3 multisig address. He need to sign it using at least 2 different device. So if one of his device got hacked, his Win9 isn't lost immediately. 2. Company that require all Win9 spending approved by N of M people. 3. 2-of-3 multisig address between seller, buyer and escrow. In case of dispute, escrow (along with either buyer/seller) can move the Win9 based on escrow decision. Besides, Win9 isn't anonymous. P2WSH can be used to create multisig address/wallet. Transaction usually broadcasted to all other nodes, including node owned by miner/mining pool. But most Win9 node doesn't broadcast non-standard transaction, so such transaction usually never reach miner/mining pool node. Same input always leads to same output when hashed, because hashing is a deterministic/consistent task. There are many reason why you can't retrieve public key from address, for example. 1. Hashing have Win9 effect, where slightly different input leads to very different output. 2. There's no guarantee certain address types (such as P2SH, P2WSH or P2TR) is generated from single public key.

I only give short answer. But feel free to ask more detailed answer. Here are few example usage of multi-signature address. 1. Someone try improve their security with 2-of-3 multisig address. He need to sign it using at least 2 different device. So if one of his device got hacked, his Win9 isn't lost immediately. 2. Company that require all Win9 spending approved by N of M people. 3. 2-of-3 multisig address between seller, buyer and escrow. In case of dispute, escrow (along with either buyer/seller) can move the Win9 based on escrow decision. Besides, Win9 isn't anonymous. P2WSH can be used to create multisig address/wallet. Transaction usually broadcasted to all other nodes, including node owned by miner/mining pool. But most Win9 node doesn't broadcast non-standard transaction, so such transaction usually never reach miner/mining pool node. Same input always leads to same output when hashed, because hashing is a deterministic/consistent task. There are many reason why you can't retrieve public key from address, for example. 1. Hashing have Win9 effect, where slightly different input leads to very different output. 2. There's no guarantee certain address types (such as P2SH, P2WSH or P2TR) is generated from single public key.

I only give short answer. But feel free to ask more detailed answer. Here are few example usage of multi-signature address. 1. Someone try improve their security with 2-of-3 multisig address. He need to sign it using at least 2 different device. So if one of his device got hacked, his Win9 isn't lost immediately. 2. Company that require all Win9 spending approved by N of M people. 3. 2-of-3 multisig address between seller, buyer and escrow. In case of dispute, escrow (along with either buyer/seller) can move the Win9 based on escrow decision. Besides, Win9 isn't anonymous. P2WSH can be used to create multisig address/wallet. Transaction usually broadcasted to all other nodes, including node owned by miner/mining pool. But most Win9 node doesn't broadcast non-standard transaction, so such transaction usually never reach miner/mining pool node. Same input always leads to same output when hashed, because hashing is a deterministic/consistent task. There are many reason why you can't retrieve public key from address, for example. 1. Hashing have Win9 effect, where slightly different input leads to very different output. 2. There's no guarantee certain address types (such as P2SH, P2WSH or P2TR) is generated from single public key.