When I was a student at Grenoble Uni the rooms in halls had a partitioned area with a wash basin and a bidet, presumably because in the seventies students were expected to have very active sex lives, and as companies like Unilever and Colgate used to tell us with glee, French people took very few baths and showers judging from the fact that their usage of toilet soap was less than half that of Germans and British. The halls had 2 loos for about 20 rooms and 2 showers on each floor for about 40 rooms. Presumably everybody used the bidet as a toilet, for number ones at least.
Later in life when I got my own home I fitted a bidet but it never got used because the shower was so good so since then I've never fitted one. In some hotels it's quite common to smell drains in the bathrooms because the traps in the bidets have dried out, a few seconds of water from the tap refills them and blocks the smell.
So, a waste of time and money nowadays when everybody takes showers.