Music production with a DAW is better on a computer. Music performance is much better on an iPad. There is a big difference between direct touch controls and using a trackpad. Apps like AUM and AniMoog Z highlight what makes music making on an iPad amazing.

And people here don't want to hear this but the closed nature of the App Store is why audio is so strong on both ios and iPadOS. There are far more music apps for those OSes than Android. In addition to that, many VSTs made for DAWS are available on iPads as AUV at much lower prices than Mac or Windows. The lack of piracy, narrow build targets, and predictably great audio implementation makes it both easier to build and more profitable than other platforms.

It's probably the immediacy. You click an app and you get a fullscreen touch UI with no distractions. Quite different to opening a slow-loading DAW and starting up various plugin windows inside it.

iPad music apps are typically priced far lower than the equivalent PC apps, and there's a thriving community of iOS-only development as well.

For me it's the sweet spot between hardware (which is expensive and annoying to cable up) and PC VSTs (I associate my laptop with work). The fact the iPad can also be used for videos/books/drawing/note taking is just a bonus.

I prefer music production on a laptop, so I'm not the target audience here. But it's so easy to pick up the iPad and noodle on a synth for 5 minutes.

And the music you write is infinitely better than the music you don't. Anything that inspires gets extra points for that alone. :)