Cadena post above yours mentioned quite a few use successful cases, all built on top of Ethereum or copy cats (Ethereum is by itself a successful use case)

Without thinking too hard, Aave is shaping to be a giant by its own as lending protocol.

Circle recently had a very successful IPO.

Farcaster and Lens are attempting to compete as social network platforms (surprisingly they lack much of the toxicity that comes on the most known ones)

And lastly don’t forget Polymarket, which is pretty well known beyond the crypto space.

The list goes on and on if you care to dig a bit deeper

All of these are at best nice prospects and most of these are just services which are only useful if the space itself is useful. I'm sorry but I'm not convinced of utility by layers upon layers of "successful" protocols.

I wouldn’t call polymarket a nice prospect though.

I wouldn't call gambling a productive usecase though.