Cosmos is one of the best framework that I know of to create entirely new layer1 blockchains. There are other uses for Cosmos for the creation of bridges, DEX, staking, etc. It's really meant for blockchain developers more than individuals. It can significantly reduce time to market while building new decentralized services and products.

Some notable projects built on Cosmos:
Notable children of Cosmos include Terra ($LUNA), THORChain ($RUNE), Binance Chain ($BNB), and Crypto.com ($CRO). These are but a few of hundreds of projects part of the Cosmos ecosystem.