I know this is how people in the 80s and 90 imagined the future and a lot of concepts were probably too far fetched for them.
BUT... why arent they using drones to explore planets? why are there not more drone-spaceships? why does enterprise need a crew to begin with? Why is there so little automation? Why so few uses of AI in general?
I am saying this as a star trek the next generation person. I'd also expect them to have full video and sensory streams of any surface mission teams.
I had no idea about this tbh they come of as very tame weapon, especially the whole stun setting part.
It can be used that way, sure, and the Very Civilized Starfleet uses them conservatively. But a beam weapon that is capable of disintegrating anything (unshielded) that it touches is crazy powerful. And those are only the hand phasers; we don't often see the phaser rifles, but holy heck. If phasers scale like projectile weapons do, a single phaser rifle would be capable of vaporizing entire buildings, tanks, aircraft.
Wouldn't a simple mirror be enough to reflect the rays back to the sender?
Phasers aren't lasers, and the beam isn't light; so, probably not.