I think practicing long shots, even as a fun comaraderie-building, friendly-betting competition like many WNBA teams do in practice, would almost have to help at least a teeny bit.
For instance, if I am a celebrity athlete who has never thrown a baseball from a pitcher's mound, but am one day asked to throw out the first pitch for a local pro team, chances are my pitch will be way off because that distance is hard to judge if you've never thrown it. Lots of people throw first pitches way short of home plate.
But if I've practiced it, even three times, I get a better idea of how much harder a person has to throw it to get it there than they otherwise would have thought without trying and failing first.
The accuracy thing is mostly good luck for most non-three-shooting players IMO, but the key is to give yourself a chance by at least knowing generally how much strength it's gonna take to heave it that distance.
One of my favorite Seattle Storm practice videos is of Mercedes Russell winning the day's hundred with her half-court shot. She shoots them regularly because one just never knows when it might be necessary in a game!