for thinner stocks that don't flip that often, you prefer to pay so you get the fill. The pay routes to add liquidity like BYX and NQBX are always the first to go on the level. To post on ARCA or EDGX or any other phat rebate market is to only get filled if it flips.
It's the difference between making 4 cents or 5 cents. Which might not sound like a lot, but when you are trading 100k shares in a $5 stock, it very well might be.
