Boost to the offense
The first reason is an easy one as the addition of Stefon Diggs is a boost to this Bills’ offense. It has a positive impact on Josh Allen, as well as John Brown and Cole Beasley.
Stefon Diggs has been a productive wide receiver during his time with the Vikings and in five seasons never finished with fewer than 53 receptions or 720 receiving yards. More importantly over the past two seasons, he has broken 1,000 receiving yards each season and has 15 total touchdowns over that time.
He now gives Josh Allen a legitimate weapon in the passing game but should help open up the field for everyone as well. Diggs is a wide receiver that commands the attention of opposing defense and they will focus on trying to minimize his impact.
This means John Brown likely now gets more single coverage, which is a winnable matchup, or defenses need to keep safeties back to protect against Diggs big play ability, which opens up the middle of the field and underneath routes for Cole Beasley.
While the Bills are still likely going to utilize the run game and Devin Singletary, the passing game should really open up in 2020.