I thought Bill spoke pretty intelligently on this.
It's really more about how backward the NFL is regarding gameday technology. Most clubs are using technology in much more advanced ways at their facilities. Then they go to the games and the league sends them back in time. They have to use computers like photo albums and the league doesn't allow the team QA access to the tech. So it inevitably throws up on itself.
Belichick is 100% right on this. He's probably 5 years ahead of them. He sees a system that's broken. He likely uses a phone everyday that's more useful than the tablets he has to use on the sidelines that get gimped by the NFL. As the preeminent coach in the league, rejecting it publicly will generate conversation at future league meetings and maybe it will get to the right solution just a bit faster.
MLB has a much more enlightened view of tech in the dugout. Basketball, even at the college level, is ahead of the NFL. Racing blows all of the major sports away. F1 is basically right there with silicon valley and Seattle/Redmond regarding technology innovation.
Sideline tech should be like a team's strength and conditioning squad or pro personnel department - an advantage to teams that embrace it and a disadvantage to teams that sleep on it. Don't create incentives for ignorance and pretend it's in the interest of fairness.