Swapping an old bathtub for a walk-in shower is one of the most common bathroom remodels we do. It makes a bathroom easier to use and easier to clean, and done right it lasts for decades.
The important work is hidden. Tile and grout are not waterproof, so a shower needs cement backer board or foam board on the walls, a continuous waterproof membrane behind the tile, and a shower pan sloped toward the drain. Skip any of these and water eventually ends up in the wall or the floor below.
Plumbing usually changes too. The drain moves or gets resized, and the valve is often moved up the wall for a shower-only layout. Built-in niches have to be framed and waterproofed like the rest of the wall.
Before you hire anyone, ask what waterproofing system they use and how they slope the floor. A contractor who answers clearly is a contractor who builds it that way.
Once the structure is right, the fun part is choosing tile, accent strips, the niche, fixtures, and glass. That's what you'll see every day, and it holds up because of what's underneath.