I think you'll get a lot of opinions on e-locks. :)
I think they have improved dramatically over the years, and good ones have ways to get in if the batteries die. Even cheap ones do.
The only electronic locking safe I have is a super cheap Barska three long gun corner safe that i have always used at my bedside if there are kids or other guests in the house. It has a biometric lock, and once I figured out how to index my finger for the fingerprint reader, it opens every time on the first try. If the batteries die, I can either use a key to get in, or else plug in an external battery pack that came with the safe to power it long enough to open up and access the main batteries.
That said, my two big safes are old-fashioned S&G. Reason being that they store my safe queens and other guns and valuables that I'm never in a hurry to get to.
If I only had one safe, I would likely make it electronic to be able to quickly get to the defensive guns, at least if I lived where I needed to keep them locked up all the time. Or else make it a mechanical safe, but also buy a smaller security container with a fast access lock for the anti-bad guy guns.