Wallpaper is making a 'slight' comeback.
I have hung many rolls over the years, and it really has a purpose.If one has a old house, and can not replace the walls...or painting would not look great, due to uneven surface's...then wallpaper is a better option.
I would never wallpaper in a new home, or one that has nice straight even walls.
Wallpaper is 'dating'.By that I mean....it really has had it's day for home decorating...except in certain homes as I have just pointed out.
It can hide a multitude of sin, but you can't rush the job...and you always need to download off the Internet advice 'how' to hang it.
Countries like England will always use it.
It is not cheap to buy, and then you have to buy all the other gear...to hang it and glues ect.In time...one could get quite sick and tired of looking at it too.
With painted Walls they are easy to change, if you want too.
Practical = Paint Economical=Paint
You could also after painting add a " Decor-Sticker"....if you want to give the room a lift! You can buy them on eBay or look into a Google site.
Easy to put on, nothing needed...and! they come straight off.You can get plenty of different designs too.Not even expensive.
Have a look at the pic I have added with this answer, to give you an idea.
Make sure if you are painting to buy a GOOD paint roller, the cheap ones are not even worth the time, they leave a awful finish to the wall that has been painted.