I'm wondering if there was a time when liquid wax was the new thing, and greeted with similar skepticism by the paste wax adherents, and history is just repeating itself.
Hard to apply? I haven't tried the spray on/rinse off varieties, but for the spray on/wipe off waxes, no. Using too much, or in the wrong conditions can result in streaking, but the same could be said of other types of waxes.
Durability? I've found that Griot's 3/1 meets, if not beats 845, and it isn't even the most durable spray according to one test. It's also faster to apply, easier to touch up, pops more, can be applied to trim, won't build up/leave white crust in crevices, and in more severe duty (on wheels) doesn't fade as fast as 845.
As someone with declining enthusiasm, and wants to spend less time on detailing, and more on other things, there are no downsides, or reasons to go back.