Just because they survive in a small tank is not a valid reason to keep them in a small tank.
You can keep danios in a 10 gallon tank, but I would never have them in anything less than a 20 long. Bettas can live in cups, but doesn't mean you should keep it a cup.
And please re-read my post, I said most, not all.
most is not correct. DP is one type of puffer, and ALL DP require fresh water..
what you meant to say was that most puffers (in general, not drawrf) require BW.