First mainstream blockchain app?

Despite 2021 being a major bull year, crypto currencies and blockchain technology are still scarcely adopted/understood.

Many people who have only a basic awareness think of it like gambling and stock market stuff.

What do you think will be the first mainstream & highly adopted blockchain based application?

I’m talking about an AOL for email + chat, Netscape for web browsing… that was the first time that the internet began to be widely adopted and used mainstream.