1. I carry AIWB and feel significantly more comfortable holstering when I can thumb the hammer when inserting. If my shirt or something is in the holster, the gun cannot go bang end my life. I'm 100% comfortable carrying my P-01 appendix. A Glock allows the same assurance with the installation of a striker control device. Some poo-poo these, but holstering might just be the most dangerous thing we do with our guns so I really appreciate this added level of safety. For those not familiar, see here:
https://www.youtube.com/watch?v=Bz7xYMChXjo
2. Sig P365 and P365XL have a single point of failure on the mechanical safeties on their guns. If the "foot" on the back of the striker breaks, the gun goes bang. This is true even if it has a manual safety. The glock internal safeties are designed in a much more resilient way. See this video for details
https://www.youtube.com/watch?v=_D03ms4E3VI
3. Fully tensioned striker vs partially tensioned. This combines with #2, in that if #2 fails you're done - the striker is fully tensioned and ready to shoot your junk off. With the glock, even if all the other safeties failed (damn near impossible) and the striker released, it still won't set off the primer because it's like 1/3 tensioned.
On a glock, it's damn near impossible for it to go off without actually pulling the trigger. And it isn't possible to pull the trigger while holstering, because my thumb will be on the back of the slide. It's also a very low chance that i'd have an accident with the Sig, but it's definitely higher than with the glock. And this all goes away if I am willing to get used to the grip angle on the glock.
Can of worms officially opened.