I have crossed there MANY, MANY times over many years and also at other borders. There are zero issues paying in USD over Baht or vice versa. Notes must be in great condition, that's all.
Yes although money changers are much better. They're everywhere now...not just in Bangkok or tourist places like Pattaya and Phuket. Most larger towns and cities have money changers, from Mae Sot to Lampang, Nakorn Ratchasima to Khon Kaen, Udon Thani to Nong Khai, Ubon Ratchathani to Surat Thani and so forth.
Nonsense. Nong Khai is the Thai side, Thanaleng or Vientiane is the name for the Lao side. Get it right or people will be confused.
No one has ever demanded payment in one currency over the other. You ALWAYS had a choice.
Also, there are MONEY CHANGERS on the Lao side. You can purchase Lao Kip right there. Duh!!
Not to mention there are money changers stocking Lao Kip in Thailand. Might not be easy to find (except in border cities) but money changers are definitely able to purchase Kip and sell some, if in stock.
It is in my opinion. Considering the proliferation of money changers in Thailand, it's easy enough to get some foreign cash (in this case USD) without putting much effort into it. Of course if you apply for a Lao evisa (which is more expensive than the Lao visa on arrival) you probably won't need to bother exchanging any money at all.
That's exactly what I meant! Thailand isn't interested in what Lao imposes or what currency they prefer. Incidentally, you CAN pay for your Lao visa with Kip. They'll charge you more than in USD but less than if you pay with Baht.
Its worth it. Very easy to exchange money without wasting time especially if you're driving to Laos or catching a bus or even if you're flying there, at the airport there are money changers.
In Nong Khai? I doubt that. Do you mean on the Lao side? That would be Thanaleng or you can simply call it Vientiane. I doubt the Thai side encourages the exchange or use of USD in any way, nor would they care about what happens in Laos.
Sure. Find a money changer for better rates than banks. 30km out of Bangkok is still Bangkok. Do you mean 30km from downtown? You can exchange currency easily and quickly at Att U park on Bang Na Trad road near the airport. Or at any shopping mall, such as Future Park Rangsit (I'm just guessing where you are...so have mentioned these places as they're both approx 30km from downtown though in different directions).