Dapper does have very low-level basic functionality to insert or update entities. You need to write the SQL yourself so this gets very painful very quickly for complicated models where you want to persist child objects.

That someone would say "Dapper is all they need" leads me to think they only work on very small projects. You will drown in large projects if you use Dapper everywhere. Better to use a high level ORM like EntityFramework and sprinkle in some Dapper in performance critical code.

The only time EF creates performance problems is when the developer doesn't understand the concepts behind SQL. This isn't an ORM problem, it's a training problem.