Overall, a bathroom must be nice but taking advantage of each space. In other words, what we call smart design
A seat space may look OK, but I don't think that it will be useful
This is a DIY idea I saw few weeks ago in a design expo
Get a dresser combining with the style of your bathroom. It can be an old piece of furniture, even used. You can paint it and set it as the focal point of your bathroom
In a store specialized in storage or even in Ikea, buy a bench and table sliding set, with legs. As a matter of fact, they are multipurpose sliding boards. installing them at different heights inside the cabinet (one as a bench and other as a low table) you will get a perfect setting for a bench + pedicure foot spa
Something like this