I was already typing a similar story like this (acoustics, audio and mics is one of my expertise), but you already got everything pretty much.
There are a few little details I don't completely agree on, but meh you need so much context/explanation to make that more clear, so we just leave it.
What I can add is that you always want some sort of cardiod pattern to keep the 'room noises' down or prevent feedback.
Obviously they are making some sort of compromise costs vs performance with this.
Btw, this mic is also mono (read the manual!)
("For stereo miking, use two Go Mic’s" and "Set up a mono record track in your DAW")
So you could have known that these are not a stereo pair, but form a summing pattern as Doug said.Never mind, apparently you can choice what to use.
As on the website: "Thanks to its switchable cardioid and omnidirectional pickup patterns, you can pick whichever pattern is more appropriate for your specific situation."
So you still could have known
Just some practical information.
Most (cheaper), small devices all have these little buggers.
A lot of times they might look like a fancy other type of mic, but that's just marketing.