Swimming pool liners were originally introduced as an interior finish for the low budget end of the market. The construction is of seam welded plastic sheeting. They can be printed with variety of mosaic patterns, tiled borders etc. But there is no getting away from the fact that they are essentially plastic bags. And as such are very susceptible to scratches and abrasion. In addition they also suffer from the migration of plasticisers from the vinyl, the process of which results in the vinyl becoming brittle, and that’s not all. If a liner type swimming pool is heated in excess of 30 degrees, there is a chance the colour / print could fade away.
For the reasons stated above we would always advise an alternative interior finish.