What you experienced was normal. Unfortunately normal rarely gets posted on Facebook. I have been traveling to Thailand since 1989. I have never been asked about how I am going to finance my stay. Only once have I been asked for my onward flight.
of course it will work. That is the whole point of it the hotel registers you online. You go to immigration and fill in a TM7 Application to stay form. The details match, bingo you get a 30 day extension.