Years ago I would be frequently asked the question, “Should I line my walls or have bare plaster?”
Not so much now. I guess people find out on the net.
However I didn’t easily find an answer when looking so here is my attempt at a simple answer.
There is no finer finish than newly finished, polished plaster, painted over with a brush-yes brush not roller.
Or if you really don’t have the patience to swing a brush for hours, use a short haired roller to avoid most of the roller texture.
If your walls are older and prone to general cracking or annoying hairline cracks then use lining paper.
I have found that some lining papers although they are simply flat paper have some texture or very slight waviness that shows up after painting. I’ve had most success with 1400 grade paper.
And if lining paper does give you, as some say, a noticeable degree of thermal insulation then the thicker 1400 grade would give you the best returns on your heating bill.
Of course there are specific (very thick and spongy) thermal lining papers if you want to go down that route or have a particularly cold external wall. Lining paper has acoustic noise dampening properties too I expect but you would have to ask one of those sound physicists or whatever they’re called, as to degree.
Lining paper will cover up some sins but not a multitude. In fact it will amplify any specks or grit left on the wall. Yes the walls need to be thoroughly prepared and sanded before lining paper is applied. Plenty of sealing or sizing the wall too is needed so as not to have the plaster absorb all your paste, dry out and cause the paper to come away.
That finally brings us to the most common gripe about lining paper; if badly hung the joints are prominent and prone to blowing loose.
Old walls use lining paper
New walls use paint
Hope that helps with your decision making.