Yeah. There's plenty of other ways to test parts, but for me, moving stuff around is dreadful. Probably my least favorite part of gaming. So much so that I put wheels on all of them. I also have different resolution games, and a 25" monitor at a height above my head. Agree about final adjustments. I meant for things like convergence, testing after a cap kit, adjusting yoke position - far easier on a table. And a TPG is far better for testing a monitor in a different room, floor, or building.
Once in the cabinet, like you say, there might be some more adjustments for brightness or position. Heck… I sometimes adjust them out of the blue just to try to get all of them to have the same color balance and brightness. Just trying to get everything as perfect as possible.
Anyway, I highly recommend a TPG, lots of very handy uses IMO. Including Phet's problem here which probably would have been resolved weeks ago if he had one. I used to have a game mounted to a board, but even that wasn't as good without all the various colors, patterns, and resolutions.
My only regret is not spending little more $ and getting the craftymech version. Mine is the pcbjunkie version which is a small, loose board, and has a couple of bugs that can throw you a curveball.