It has nothing to do with how you submit the TM30. It's about several immigration offices not accepting TM30 receipts from hotels and guesthouses.And I don't think "most people" submit their TM30's online. Who told you that?
I don't know if any "perks" are worth 650k. Don't forget that the Elite visa was designed for people under 50 and for people coming and going as they please. As a retiree staying in Thailand long term it's imo just a waste of money.
Why do you think the price for the cheapest Elite visa went down from 900k to 650k and might be even cheaper? Because no one wants it since the DTV was released.