different cultures and Thai girls are just not mentally and psychological ready to live in western countries. Don’t be surprised if she leaves without you knowing. Sure there are exceptions but how many are open minded, communicative, culturally adaptive and independently minded ? If she is , doubt you will find her compatible
They are looking at a commitment like a long term visa if you are planning to stay for a longer period. Otherwise as you say, just be a normal tourist.
It makes sense to the government to filter out the undecided ones.