I don't think I'll ever understand these Loans with option to buy clauses.
If the player does shit, send him back (Former club wouldn't want him either)
If the player does well, they keep him (Former club may be willing to give another chance)
It always seems a win for the potential buyers.
Now a loan with an obligation to buy makes sense.
"Loan with obligation to buy" isn't a loan at all. It's a pretty obvious FFP dodge.
It's an "outright purchase with a deferred payment".