As an owner of an Instant Pot that gets regular use, and another pressure cooker that lives in storage now, I think I can take a stab at it:
Compared to stove top pressure cookers, it's just easier. Stove top ones require constant attention and fiddling to manage the heat an pressure properly. With the Instant Pot, put food in, close lid, set time, go watch One Life to Live reruns until you hear beeping.
Compared to other electric models, it's either cheaper, or easier to use, or both. Many comparable models are prohibitively expensive, while the Instant Pot is $100. And the interface is dead simple. Push button, adjust time, walk away. I haven't used another electric model, but a couple friends have them, and, to hear them talk, theirs aren't quite as simple to operate.
(That first step might be more confusing before, probably by the 3rd usage, you realize that all the buttons labeled 'bean', 'soup', 'veggies', etc. all do basically the same thing and are really just there for show.)