It's of course possible that they have (or will have) some that would be covered by an implicit grant - though you'd need to go to court to confirm that.
But it's quite possible that they could have many patents
that cover non-substancial parts. Guess what? You're now in violation of those if you haven't already licensed them.
So, again, even in the best case the implicit grant still requires you to go to court to maybe get clear of some liability.
Explicit ones have you covered from the start. More rights for you, broader coverage for you.
It seems very unlikely to find a way to use these products in an unintended way that would violate some tangentially related patent, but a) it's all hypothetical and b) one should never underestimate the ability and willingness of IP lawyers to allege an infringement.
"You have stored the software on electronic media and used that media as a doorstop, violating our access control patents by keeping the door open."
Yes, the grant is better than nothing, but also, the risk if the grant is removed seems minimal.