But even if they don't (eg Uber) they still have all sorts of first party data that comes with some form of privacy consent, which makes it valuable in itself, but much more valuable as we go through the ‘cookie apocalypse’ and remake how online targeting is going to work.

Existing crypto wallets like MetaMask have been built to process and track transactions. Increasingly, however, wallets serve as a place to track digital goods and experiences – becoming an extension of identity. That may benefit newcomers like Genesis. 

Wallets holding NFTs are public and composable databases.  Anyone can do an airdrop to Punks holders, if they so wish to target that consumer segment.  Wallets are a marketer's dream email inbox. But the UI is still early and primitive - think about all your spam airdrops.