I think measurements are very important when it comes to certain aspects of the game. Defense in general is dominated by long wingspans. Rim protection is the most important. Bagley's wingspan is about 4-6 inches shorter than the majority of the good NBA centers and it's a big reason why his rim protection is so poor. Richaun Holmes would probably be a completely different type of defensive player if he had a longer wingspan. On the other hand, Robert Williams is 6'8" with a 7'6" wingspan so it's no wonder he had 8 or 9 blocks in a playoff game.
I wouldn't pick a lesser player due to his measurements but if two players are fairly equal and I need defense and one has a much longer wingspan than the other, I'll pick the wingspan because his odds of becoming a good defender will be higher. Guys like Jimmy Butler who are all world defenders with short wingspans are few and far between.