My iPad has 32 Gb, even more than the laptop that I use right now (16Gb).
And I don’t see why you need Ethernet… Actually I’m not using Ethernet on HA, the laptops is hidden and it’s connected via Wifi.
Why you need ethernet? Stability. Wifi is…well, kinda “unreliable” on longterm 24/7 basis in a term of connection without ANY dropouts. I have cameras around my house and one of them was on wifi (lack of cable). It went offline every now and then for a short time. Cable solved this problem. Now, it’s not important for camera, but it is for HA - you don’t want HA to go offline just when you are switching something…
The point is that wifi is pretty congested, so HA on wifi would cause non-stop traffic through already busy wifi, making it even more congested.
But, i think that pretty big no-no is lack of processing power, too. I have not so old lenovo 10 (android 10) inch tablet as lovelace view in my kitchen and it struggles just when switching between views. I can’t imagine how slow it would work if i’d have HA server on it, but i guess it would be painfully slow.