Is it worth converting a bathtub to a walk-in shower?

In a primary bathroom, usually yes, because the tub in that room is rarely used and the space buys a far better shower. In the only full bathroom of a house with three bedrooms or more, think twice: buyers with small children still look for one tub, and removing the last one narrows the market when you sell. The work itself means moving the drain, rebuilding the floor slope and waterproofing properly, so it is not a surface job.