The L2, which is real-time info will help you(if you are watching it) on a certain day or days or whatever time frame(as long as you are watching) to give you idea on the support and resistance of the stock price...
examples: is the support holding or is it being knocked out?....is the resistance falling or does it keep getting replenished/blocked right as it is getting ready to uptick?....also who are the active MMs, are they known to be or appear to be sellers or involved in dilution such as you have been hearing about with OTCN...things like that is what the L2 will help identify, which might aid one in keeping their holdings or selling them...
so you don't have to have L2 to invest...it just helps you watch the behavior of the market along the way...as for long term vs short term holders I would say that short term would be more likely to use the L2 as an entry and exiting tool.
Hey here is a strange question. Is it ok if I invest my money in a penny stock I like, Like AFFU even though I don't use LEVEL 2 YET.??