I have found the tools are of higher quality that the fittings. the bolts always strip regardless of what tool is used.

I also usually tape the tools to the underside of the furniture to use should it need to be tightened or deconstructed for moving.

I keep them.

I recently sold a metal bed frame which was assembled with hex screws, and it was good to be able to include the hex tool that came with it, so the person who bought it had what they need to put it together again.

I like printing handles for them!

https://www.thingiverse.com/thing:2108540

I'm less concerned about the quality than the effort. Using an electric screwdriver will literally half the time it takes to make the furniture piece.