Why a tub spout in a dedicated shower?

I've noticed in some showers, people have elected to install a tub spout near the floor, using a typical tub/shower valve kit.

Any reason for this vs. a dedicated shower valve kit? Do people do it to get water up to temp and get into the shower before turning on the spray? Use it for cleaning the shower? Draining the pipes leading up to the shower head? All the above?

Just curious. Too late for me now - I've installed my corner shower with a Porcher Reprise shower kit, with no tub spout. Just curious, as my old shower had it, and some friends who live in newly built homes have them.

It allows you to get the shower warm before spraying all over the place plus, it gives the pipe a chance to drain so you don't have a slug of cold water in there in case you forget!

We installed our dual shower like that. The spout is a good toe-tester for setting temperature, good for filling buckets, and good for washing dogs. Not so good for washing cats, I've found.