If Alex is doing a simple bounding circle,or AABB check before the more detailed polygonal check, then it shouldn't make much difference at all.
That might be an optimization he hasn't bothered with yet though; same for spatial partitioning.
Imo overly simplifying the collision bounds at this stage is premature optimisation given the alpha status of the game.
The game is doing both a bounding circle check (that's what "collisionRadius" is for) and uses spatial partitioning. Both because they were found to be necessary, not "just in case" - though a bounding circle check is the sort of thing you can code in about 5 minutes, anyway.
So worst case in Starfarer is a lot of complex capital ships firing a lot of pea-shooters at each other en masse. Can't get around the detailed collision checks in that case.
Even worse when a beam is shooting at something, or when multiple ships are within each other's collisionRadius but not actually colliding - which can happen a lot, and means detailed checks every single frame, to the tune of n^2 relative to the number of bounds segments.
So, when a pair of Wasp wings fires at a ship, having a 150+ vertex bounds polygon will make a very real difference. More of a difference on lower-end computers, obviously. I'm not going to say it's a
huge deal - but it's something, and since detailed bounds are completely unnecessary, and more work to boot...