Well, firstly, we definitely need someone. Spending money on a prospect like Sane, regardless what you think of his ability, will probably cost 30 million and upwards. We can't afford it.
Gameiro is relatively cheap, proven, dependable, and most crucially would be signed knowing his status in the squad. He has 24 goals this season when Sevilla haven't been great for large parts, so you can't act like he's a nobody.
We need someone who is gonna give us 2 or 3 years of being a dependable back up while the next gen of younger guys develop whilst maintaining squad harmony. He'd be plenty adequate. So yes.