It's not just that. If you do it before the draft, you can guarantee the #2 pick in the draft, for instance.
If they trade him in August, you can't guarantee that, and in fact, you're likely getting a late pick because you're getting the 1st-rd pick of the team with Deshaun Watson at QB.
Gonna assume that I already know the answer to this
But why donr teams use conditional trades more to account for this (the uncertainty of future draft picks). I feel like when they're used it's usually by some hit-or-miss measure (ie a player is extended, or isn't crippled)
Ie we will give you next years 1st round pick, and if it's not in the top 20 we will also give you our 2nd round pick?
It seems like this is a very simply solution that would reduce uncertainty and risks of trades, especially ones where a significant portion of the value comes from an unknown future draft pick