It's exactly as you have described in my house, no problems, actually looks quite neat. Certainly a better option than gouging your nicely tiled walls.
Actually, sorry, it's trunking in my house, not conduit. It's butted up against the ceiling and the shower case (at the top and the bottom) and sealed around with a bit of white mastic. The bottom of the trunking is cut at a slight angle to match the shower case.