yeah if you are refering to a comfortable cafe to sit long for work i will agree with you the min cost for coffee is 50baht or above but i dont agree with spending just 500 baht a day on food is restricting myself. Look at mark wiens youtube for example. He introduces tasty cheap thai food. I dont see why choosing to eat cheap but tasty food is any form of restriction. Of cause i do eat 299 or 499baht pasta sometimes but dont see why i need to eat them everyday as theres really alot other cheaper tastier food.
i am not restricting myself to the cheapest big c or lotus food. You can get decent food for 100 baht or less. Also, expensive food does not mean it will be nice.
local food and coffee is cheap and nice. Usually a meal cost between 40 to 60 baht and coffee 20 baht. Theres a lot of good food choices ranging from 40 to 100 baht.