Cheap chains are cheap enough to be disposable. I'm rather embarrassed to suggest it, but for the occasional user just chuck and replace when they blunt. I suspect they blunt quicker than a quality chain, but at £5 or so, one can live with that. I suspect a new cheap chain performs better than a blunt or badly sharpened quality one!
Each to their own.
But
All depends wot ur cutting.
Very clean wood away from road stour or flood water u could be right.
I know 1 pro cutter used to do that ( I used to buy some of his chains off him for my use)
But in good clean timber looking after ur chain u can go 1 day + without sharpening.
In dirty wood or dry cheuck hard wood u can be sharpening every fill or even every 10 mins.
And a lot of firewood can be dirty ( or folk cutting into the dirt)
Makes it expensive day.
Sharpening a saw really is not hard.
Buying cheaper chain will make it harder to sharpen
As does the LP/ pico chain, a bit more fiddly than normal 325 or 3/8s.
Those cheap grinders are OK, at 40 quid not be long in paying u back.
A decent oregon chain should be lasting a hobby user literally years or 00s of L of 2 stroke.
The saving of cheap chain ( or files) is just not worth it.