Can anyone explain why they wouldn't simply do it this way?

Self-Repair: FREE: Regeneration, but only at the beginning of your turn.

Seems to get the job done with fewer words.

Probably to give it less options to be countered. You can outwit regeneration. Even if they added protected or safeguard outwit, there are still options with pieces that remove or bypass that. I'm not sure why they moved away from using the wording "can't be countered".

The way you suggest wording it would allow it to be outwitted.

I don't know who these angry robots are, but they look like the close-combat version of a second coming of the GSX Mindless Ones.

You can't give FREE actions at the beginning of your turn. It would end your beginning of the turn phase. And if you left it as Free: Regen then he could take damage and then regen afterwards (crit miss, Mystic, EE/PW blast, etc) - so timing was a consideration. In a Battle Royale, this version got surprisingly tough. I would hit it 2 times and miss on the third to put him down - then up he'd heal (player went after me). Pricey but with some good rolls / misses - will feel like more than 75 points.

Only recently noticed The Fury had been clixxed. While a reasonably potent threat it's nowhere near as powerful as the indestructible superhero killing machine that it should be.