It also benefitted them during the time they had him on loan. Then the player decided he liked it there and wanted to stay.
That could easily happen with Simons.
Surely though if that were the case then we'd just negotiate a loan with obligation or option.
There's generally a reason why it's a loan, either the club want him back for whatever reason or the player has eyes on going elsewhere.
And what's more if he does play well his price will increase anyway which will price us out the market even more so than this Summer.