All I can tell you is I find a thruster helpful and stress-reducing. Anyone who says otherwise is just being a contrarian or hasn't been in tight spots. Or is pretty good at repairing fiberglass.
In short, a thruster is not a crutch, it's an enabler. Whether you're a beginner or experienced, allows you to do things you could not otherwise do.
This younger generation years of playing games now operate boats and drones.
Peter have you got a joystick yet controlling the engine and thruster.
Our newish boat neighbor has a Marlowe with a yacht controller of some sort (dunno actual brand) and he docks using a little portable box... which must have something like the equivalent of a joystick...
OTOH, I think I'd be a total flop with a joystick, can't hardly even "drive" our bow spotlight with one... No experience, never played computer games and so forth...
Our first biggish boat was a single diesel, no thruster -- and we learned to deal with it. (Spring lines are my second-best friend, right after wifey). Then we had a twin screw boat, learned to deal with it. Wouldn't ever have turned down a thruster, being in the "anything that helps" camp, but the $$ never showed up for an aftermarket installation...
This boat came to us with a bow thruster. Nifty, I thought. So then I bonked* the swim platform a few times while docking stern to... in retrospect, mostly because I distracted myself by trying to use the thruster to do something... when I should have been simply parking the boat.
Gradually that's the way our routine has become; now we mostly just dock the boat using the gears. And then sometimes use the bow thruster when it can do something the gears can't easily manage. Usually like move wifey closer to a forward pile to get a line on it. Or very occasionally, to overcome wind/tide/current to either keep us on station while lines are being secured or to slightly lighten a hard landing if we're being pushed into a dock or some such.
Bottom line is I like the bow thruster, wouldn't turn down a stern thruster... but I've also gradually begun to recognize when it's useful and when it's a distraction.
While I understand the arguments to "just learn how to operate the boat" I don't see that as reason to NOT have a thruster if one is within budget limits. I do cringe a little when I see some docking maneuvers, where it looks like the operator likely has no clue, and probably couldn't dock the boat without his thruster, maybe without his joystick. I'd call that critique of the operator though, and likely wouldn't assume the thruster actually caused his/her ineptitude.
(* In my further defense: My bonking events were not only a product of thruster distraction. It happens I was also having to learn single-lever gear/throttle controls at the same time. That was really the more difficult learning curve, since I'm not used to having to look at the controls to see (remember) what we're doing at any given time. That at least got better with practice. <sigh>)
Back to our first boat: If it were now, I'd add a bow and stern thruster in a heartbeat. Necessary? No. Nifty? Yep. Wifey and spring lines would probably still be my best friends. Probably wouldn't care about a joystick, though; I still think I'd be dangerous with one of those...
-Chris