The way most people use iPads as 'dev machines' could be just as easily configured using a $199 netbook from Best Buy and a copy of PuTTY. (Or, buying any not-broken laptop from Craigslist for $50 and saving yourself $1100.)
Granted, as a sysadmin, most of my job could be done on an iPad too (SSH, RDP, web browser, and messaging applications), but every few days I need USB, Serial, VGA, or Ethernet (along with manual config of the adapter), among other things.
So, with these iPad there are always caveats: you end up needing to keep a "real computer" around for all the cases the iPad can't cover, which is most of them.
A few days ago there was a discussion about Termux (https://termux.com/) on Android here, and with things like USB OTG and removable storage that are commonly featured in Android, a Kindle Fire tablet (which cost about $50-150, regularly on sale) would be more usable, even, than an iPad.