Odd Argentina plumbing bathroom drains

I went to Argentina and stayed in two different, 4 star, relatively new hotels. both had similar bath rooms, with a 6 inch square floor pit , about 3 inches deep, between the toilet and the bidet, covered by a metal grate with holes in it. if you ran the shower, or the sink, the water ran into the floor pit from drain lines. The toilet did not put water into it, but THE BIDET DID?
Seems that would be putting really dirty waste water into an open area. Would this be code compliant in the US? Or do they consider the bidet to put out the same level of contaminated water as a shower?
whats the purpose of this thing?

That would not be code compliant in the US.
It may be their version of an open cleanout and floor drain combination.

There are many things that I see South of the border that don't make any sense.
But hey, it's not like they are drinking the water down there either.

The US has the best water in the world. It's what separates us health wise from many countries.

That would NOT meet the code requirement for " a trap for every fixture", plus it would fail for other reasons also.

they had traps on the sink

Well, either they were then "S" traps or the vents were either completely useless OR conduits for sewer gas into the bathroom.

what I meant to say was the sink had a p trap under it I could see. dont know about the shower (tile floor over concrete in a hotel, or the bidet (maybe a bowl trap).
I wonder if they send toilet water somewhere else different from the shower/sink/bidet water

A "P" trap without a vent becomes an "S" trap. If it had a vent, AND that vent was tied into the toilet piping, then the vent became a conduit for sewer gases into the room. But, from your description, the floor drain trap isolates the sink, etc., from the drain system so the trap under the sink was cosmetic, redundant, and nonfunctional. Using a separate drain for the toilet is a possibility, but that has NOTHING to do with draining everything else into the floor drain.

This country uses a gang trap. It looks round and has 6-8 inlets.The toilet is like the USA type with its trap built in. They do run a vent off the waste stack to the roof. The city of Mendoza Argentina has the best water you can get. This city once was desert. Mendoza sits right beside the Andes Mountains. They damed off the natural spring water gushing out of the mountain to form a very large lake in the mountains and piped the water to Mendoza.All buildings have a water reserve tank on the roof.The place I live (2 bedrooms 2 1/2 bath) has a 1100 liter tank. The water supply for this whole area (almost 2000000 people) uses NO PUMPS!!! Its ALL head pressure from the mountain lake! I married a woman from here and she has 3 plumbers in her very large family and one of them explained it to me.They also use gas tankless water heaters that work great.And gas is fairly cheap. Thats it for now the wife just got home for Siesta. This country also goes to work from 8-9 am then 98 % goes back home around 2pm (Siesta/lunch/sleep) then around 4:30-5pm they all go back to work till 9pm then home again and eats dinner from 10-12pm. Its kind of wild to see rush hour 4 times a day. 2 going 2 coming back home. She says Spain also has this custom. Later...
Did you know most people from Argentina are Italian that speak spanish.The people from Brazil are Portuguese.And most of the others in S. America are Spanish.