For the Bills, he was only going to get more expensive. Regardless if the cap drops, he's arguably the best corner in the league right now. Locking him up a lower price and not having to negotiate his deal and Milano's at the same time is a huge benefit.
For Tre, the uncertainty is probably a factor. I suspect it will be a large deposit into his bank account tomorrow allowing the people managing his money to invest it right away and have at least an extra year of investment income which can be substantial.