So because I had nothing better to do and was listening to music (Ray Charles) anyway, I decided to do some experimentation.
I set up a listening chair - but in this case a bar stool - directly behind my PLP (which is directly inside the axis convergence point) of my speaker setup. I used a bar stool because I need a bit of height clearance from my main seating position, where I sit on a La-Z-Boy 655-662 chair-and-a-half.
Mindfully, I realize my PLP places my ears an inch or so lower than the tweeters, and the bar stool places my ears an inch or two higher than the tweeters. So I guess in the strictest sense my experiment is not an exact science, however, I imagine it's close enough.
Outside the axis convergence point did sound *very* good. Difficult for me to describe. The image certainly differs. While I do prefer my current PLP inside the axis convergence point, I could also envision some use cases for being outside of axis convergence point. I guess I found a "secondary PLP".
Clearly this boils down to a matter of preference.
I didn't test thoroughly or for all that long, but both inside and outside the speaker axis convergence point sounded very good to me.
Good to know I can now add some seating if/when audio phriends are over.