The expectation is that NFL general managers will hit on first-round draft picks far more often than not.
When that doesn't happen, change is inevitable (see: Whaley, Doug). The later the draft gets, however, the less that is expected of those drafted. By the third day, contributions from those chosen become a pleasant surprise, not an expectation. Hitting on those picks, then, becomes an important way for teams to round out their rosters.
Sports Illustrated's Chris Burke recently went through the 2017 NFL Draft and identified one player from each team drafted in the fifth round or later (or signed as an undrafted free agent) who he believes is most likely to make an impact in 2017. For the Bills, Burke chose Boston College linebacker Matt Milano, who was chosen in the fifth round (163rd overall).
His explanation is as follows: "Buffalo was believed to be a possible landing spot for Haason Reddick or Reuben Foster in Round 1, so the linebackers the Bills took later deserve a little more attention by default. Milano (6' 0", 223) isn’t an elite athlete, but he reads the ball well and flies toward the action. Don’t be surprised if he’s picking up significant snaps as a rookie."