Hot water will warm up the tile in the shower very quickly. Putting warming mats under the shower would simply be a waste of money.

Not a waste of money if you want to spread heat generally, 24 hours a day.

If you want the shower area to be warm in advance, and for the walls to all be warm, and the floor too, so that you do not have cold spots and warmer spots while showering, go ahead and install heat.

If anyone needs reassurance that shower water heats the tile up, I will add to what you have read above. Yes, shower water warms up the floor and wall tile that it falls on in the shower.

hth
-d

We have a heated shower floor and I really like it. The electrical mat had to be lain a little lower than in the rest of the room, but it's on the same electrical control. So, if we turn the dial to 85, the outer area gets to 85, but inside the shower area, maybe 80. I like it, the tile is really really cold without heat, and, the heat under the shower floor makes the tile and grout dry out all that much more quickly. I don't want water standing around on my tile and grout.

But, that's just me. I'm glad we went to the trouble and expense and I'd do it again.

Maybe a good thing in Alaska? Unnecessary in California.