Good to hear it worked out well.
Being such a narrow hall with a tiny stage and 95% of the crowd in front of me instead of virtually anyone on the sides, XY was absolutely the way to go at this venue. I think XY is slept on at times. It has its place. Last night was one such occasion.
Interesting, can you expound on that? Why absolutely the way to go there? Your assuredness really interests me because I'd go the opposite route, based on each of the reasons you mention!
Why? If I were unable to run mics up at stagelip or on stage + SBD (as 1st choice, and where I might consider using X/Y). I'd most likely run PAS, and would definitely go that route if recording from the back of the room. PAS will place the mics directly on-axis to the PA and stage sound sources, improving the ratio and clarity of pickup of that content as much as possible, while picking up less room sound, wall reflections and content from behind. But by placing the mics on-axis with the PA the angle between the mic pair will become rather narrow, so unless some spacing is used between the two mics to compensate for that overly narrow angle (in effect, "trading" angle for spacing by using increased spacing to compensate for the decreased angle), the stereo effect from the narrowly angled XY pair is going to be less than what it could be. In terms of imaging, the inclusive recording angle of narrow angled X/Y pair is very wide, which doesn't match up with the narrow apparent angle the stage and PA fit into. The imaging from the pair is in effect "zoomed" way out, which works if up close, but less so from the back of a narrow room.
If instead an angle more appropriate for X/Y is used (say between 90-130 degrees), the imaging works better but clarity suffers since the mics end up getting pointed at the side walls, picking up more reflected stuff and lowering the pickup ratio of direct sound from stage and PA in the recording. For that reason, unless part of an four mic array, I'd probably only choose to use X/Y up close where the sources on stage better fit the wide X/Y recording angle.
Now, if the advantage is more about practical setup stuff - coincident X/Y compactness and small foot print in a small bar - I totally get that. And coincident (X/Y, M/S) might be helpful when the bottom end in a small room is messy and reverberant. But for clarity and image it would probably be my last choice from the back of the room.
Not casting shade, but interested in the different ways and perceptions of different tapers.. and always open to new insights. Different strokes for different folks!