Not so sure that Poch didn't believe in Bentaleb, but he wasn't able to commit to giving him regular starts either. And if the rumours/ITK (yeah, I know) have any basis in truth, then a player giving Poch an ultimatum of "play me or I'll look elsewhere" is probably not conducive to keeping in your manager's good books - nor to squad harmony had Poch given in.
Is there anything for Poch to learn from this? I don't think so really. I do sense a stubborn streak in Poch which maybe over time he might need to temper, but in this case I don't think he made a bad decision.
All total speculation of course, we will probably never know for sure what happened behind the scenes.
I'm pleased for Bentaleb that it is working out for him at Schalke and sorry for us and him that things didn't work out at Spurs.
But as you say, that's life.