Where did u read it’s limited to 10 entries ? There is no limit - come and go as you please - subject to 180 day continuous limit or 360 day with 1 extension.
If you apply in person for DTV - you get sticker. If you apply online (eg e-visa) you just get PDF. Everyone that enters on either type of visa will get stamp - usually with DTV in handwriting and 6 month validity date (extendable to 12 months)
They can be very strict, I had to go to immigration for simple residence certificate because I want to get drivers license. My landlord had done late TM30 and I was told I had to pay the fine for his delay.
The airline checkin desk are the main ones that ask for proof of onwards travel. Showing a DTV has satisfied the check in staff the 3 times I’ve been asked.