Just a couple of comments.
The NYSE have been the consumate "day-traders" for centuries, and have generally made good money. Some say from "stealing" some understand that it's mostly "providing liquidity."
My brother and I spent a decade or longer on various exchange floors, options, futures, and equities. We provided liquidity, we "scalped" (day trades), and we got involved in serious longer term positions. When trading a couple thousand options daily ( a lot back then, LOL), we would always have a few thousand open positions. Not everyone traded that way, but many did. Some simply day-traded.
When people ask me what kind of a trader I am (Scalper, day trader, momentum, Technical, Fundamental, automated, pairs, mergers, relative strength, break-outs, contrarian, etc.)... I simply say "yes, yes, yes, yes, yes, yes, yes," (you get the idea, LOL).
The really successful traders I know, both within and outside of Bright Trading, tend to not limit themselves to "day trading" or simple swing trading, but tend to use excellent entry/exit techniques in all types of trading, long and short term. For example, "pairs trading" is a strategy, but proper entry is like the tactical aspect of how you execute the trades. Some basic people think you find a spread price on a pair, and then simply execute both sides, not good, and can be costly in the long run.
Trading is definitely multip-faceted, from quick reflexes for some, to accurate record keeping, to tape reading, IMO.
FWIW,
Don
