Waterproof wall panelling is designed to be better than tiles, not cheaper than tiles.
Thee are some very cheap tiles available. But there are also very expensive ones, especially if you start looking at natural stone products.
There are few factors that ensure that wall cladding will usually work out cheaper as well.
Walls need to be thoroughly prepared to take ceramic tiles, and this can be a quite significant cost on top of the installation and purchase costs.
Waterproof wall panelling is much more forgiving and will go up over a variety of substrates without any preparation. It can go straight over existing tiles without the need to hack them off. This saves money. But it also saves time and a lot of mess.
It is also relatively easy to install so the average DIYer will be able to install wall panelling themselves.