Well, that is what I stated in the post you replied to ....but you then brought up other topics that I initially did not bring up but now responding to...Players increase in value from season to season.... Your point?
The fact is; if there was no option attached to the loan, Juve would have either kept Romero or sold him at a big profit themselves.
Lo Celso wasn't bought by Betis in the same window as he was sold by them.
Betis activated the option on Lo Celso in April 2019 and sold him in August 2019. So, yes, it was not the same window as Betis could activate the buy-out option before the window opened ...but there was no window between the purchase and sale of Lo Celso either...