Honestly it's just the QR code thing. Like paying your internet and electric bills just by scanning it. I also pay my rent with a qr code. No need to carry large amounts of cash around when you go to the club or anything like that. I just need my phone.
If you're already in thailand and on another visa it's going to be complicated. Get yourself an agent. I used this one while I was staying in thailand. She's very good. Add her on line app
I just got mine a few days ago and came into thailand yesterday. The paper i brought with me to immigrations has the type of DTV I applied for on it. I was also told because it's a E-VISA system now they can see my VISA in the system at immigrations. I don't know what their screen said when I check into the country with a DTV VISA but I'm sure they can see it if they want to. If it doesn't already say the type when they run my passport. Your stamp on your passport just says DTV though.