Well, let's work it out. If you can meet the higher spend requirement without wasting money, and can use all the points for your planned travel, you're getting an extra $375 worth of points for a $355 higher AF.

You do need to factor in the money/points you would have earned by using a different card for that additional $3.5k spend, vs what's earned on the Prestige, but that's probably less than $20; you would need to do the math.

And that's not even counting the added benefits of the Prestige, which you'll have to assign a value to.

But there's a larger picture. Unless you plan to cancel after a year, you're also committing to paying that extra $355 again, for whatever benefits (not counting bonus) it gets you.