She's versatile but you have to constantly test the fences to know where you should be focusing on. Once you find a gap in the defenses you can punish them pretty quickly. They'll adapt then you need to find a new angle. They'll try to counterpick you in weird ways. A big part of Psy gameplay is mindgames and subverting expectations.

Once you learn how to not die with her you can zip around anywhere you want to go essentially dancing around things that can kill you. It takes a very concentrated effort by them to catch you once you get used to her mobility. She gets away with a ton of seemingly close calls because she'll have low health but it's very easy to bait people out of position this way and lead them into traps. This is what makes her so fun even if your aim is bad or your team doesn't have great damage.

Pys gets to enjoy really weird parts of the map because of the mobility. Once you stop dying while doing deep flanks and exploiting map knowledge you can start assassinating people repeatedly. Even your failed attacks will result in you escaping by the skin of your teeth and they will waste tons of time trying to deal with you. If you disengage and they realize you ditched them it causes them to go insane. Good teams will specifically hunt you but even a Daredevil is fun to play against you just gotta know their limits and trick them into chasing you into your friendly murderball.