Well, Steve is experimenting with and trying out stuff like most of us are, whether it's pickups, wiring or squiggly frets, don't know what's so controversial about that. I suspect he went back to normal frets for the most part because in a live situation, unless everyone else you're playing with uses the compensated frets, it would make everyone with normal frets sound out of tune, and vice versa. If you're just alone in the studio, then it's fine, as you're in full control of the musical situation. He probably felt that, for himself, there were ultimately more trade-offs in using TT frets than regular ones for most musical situations. Maybe the practicalities of the system and getting it done were also factors, as mentioned in the thread.
People complain about how much the Jem and Pia cost these days, well, can you imagine if Ibanez released one with TT frets?
It's a pretty labour intensive process to make/install these compared to straight frets, the mark-up on a production guitar would've been significant. As an example, Matthias Eklundh's Caparison is over 6k.
The TT frets are just one out of several possible ways of subdividing intervals in the octave to allow certain ones to sound more in-tune when playing combinations of notes. In the Renaissance and Baroque periods, lutes had tied on gut frets so players could adjust them according to the keys of particular pieces. So if you're playing in major, for example, you could tweak the frets to make major thirds sound more assonant etc. Bowed instruments, being fretless, don't have to deal with this, as it's down to the player's sense of intonation and finger placement.
Conventional frets on a guitar are a kind of averaged out compromise, so we can in all keys and it sounds ok. This also applies to the piano, the strings of which are tuned to allow all keys to sound pretty good. It's an interesting concept for guitar and has been around for a long time, going in and out of fashion in the mainstream. Personally, I don't think it's a gimmick, it's just another facet of the guitar which is available to folks who want it and can pay for it, and it's cool that that's an option. It just shows that it's a great time to be a guitarist Ė lots of choice in gear at different price points.