Epicbo:
On the other hand, if you have a lot of CK, CD, hero kills, etc... but still lose, it doesn't matter because you're going to lose PSR.
Or if you play a babysitter/support, and after 10 minutes you realize all your carry/semi-carry heroes are shit, so you're standing there with 30 denies and 4 wards placed after 15 minutes and your hero stats are 0-1-10. You lose the game, you lose PSR.
In these cases TSR will be more accurate. And let's be honest: They are far more likely than the one you mentioned. (I'm talking about pubs and games for normal people like us. High-level competetive games aren't AB'd anyway, so neither PSR nor TSR will do any good.)
I have TSR installed, but don't use it for balancing, I just use it out of curiosity. For example which enemy player I have to look out for in pubs, or which hero I'm going to ban (if there's a 7.00 TSR player with 30% devourer out there... well.)