I use this one too. Works fine for wheeling pins around inside and outside. I've also used it to haul pins up sets of stairs a few times--the big wheels help. However, when I do that, I take off the backbox and remove the playfield from the cabinet, and just use the hand tuck for the cab and backbox (and strap them to it), and hand carry the playfield.

You can also take off the wheels, so it's easier to store.

An escalera would be much, much easier and less time consuming, but that piece of equipment is also rather expensive.

Weight. The cabinet body isn't quite as heavy when you remove the playfield. Less weight means it's easier to haul up the stairs. And since I've already disconnected everything from the backbox, disconnecting the remaining cables for the playfield is fairly trivial.

Once the cabinet is up the stairs, I put the playfield back in.

I can't speak for the stair belt, but with a hand truck on wheels, I can stop and pause while going up if I need to adjust my grip, or the load, or just rest for a moment.

That said, it's harder go down the stairs (safely) with a hand truck than it is to go up.