Solvers are useful for confirming that a puzzle you've recieved or generated is solvable. The meditative process can really go sideways when there is no solution for you to stumble upon.

Puzzles in commercial collections don't usually have that problem, but those from other sources sometimes do.

Solvers also make for a nice craft exercise, as here. Simple but not trivial, you can approach them in a lot of different ways and thereby work through different techniques or constraints you mean to explore.