Most Bitcoin users will not relate to this as transactions on the network are mostly straightforward, you enter an address you want to send to, pick a feerate and then sign the transaction. Clear signing is useful when you are interacting with other features of the crypto world like dApps and smart contracts which involves third parties that could be trying to scam you.
Ledger is the one wallet I know which added clear signing to their system.
The article you linked explains why Bitcoin addresses look like long strings, not transaction calldata.
What Clear Signing refers to is hex-encoded calldata / contract calls, not address length.
Multisig addresses may involve more complex scripts, but users are still signing a transparent BTC transfer. Blind signing becomes a real issue mainly when interacting with smart contracts and dApps.