Because it's cheaper and easy for self-management. (Since I travel for 2-3 months each time.)
I don't enjoy cooking as hobby. I cook myself not to die for hunger. So my meal is simple, nutritious and sometimes looks not pretty :p
And since I mainly use AirBnB to stay, I respect the house rule to use my host's kitchen.
Even if they don't have specific rules for cooking, you should ask your host what you can do and cannot do in their kitchen, using their tools.
Some people don't appreciate the smell of cooking meat/fish.
So I'm keen to learn cooking meal which is simple, quick, cheap, nutritious, smells not too strong. And easy to clean up.
Let's call that roaming meal.