What's the reason for cooking food in the afternoon and then leaving it out for later during the day?

I saw my Taiwanese MIL do this, and I'm wondering if others do it as well.

She'll cook some dishes in the afternoon and then just leave them covered on the table for the rest of the day to eat at dinner. She might heat up a few things when it comes to dinner, but typically it's room temp.

I'll I can think of is bacteria growing since it's in the "danger zone." That's not safe right?

Also, I swear she uses no seasoning in her food, but I don't think that's very common.