A person won't get much if he would invest in Bitcoin short-term. And a person probably doesn't understand Bitcoin if he invests into it that way.
Before doing steps like that and DCA or buy in lumps, a person should consider all the risks, analyze a big chunk of info needed, and keep acting toward the goals in his mind.
investing in bitcoin for short term does not mean lack of bitcoin understanding rather it is choice and everyone investor has different choice and approach so saying they do not understand bitcoin is a wrong statement remember not everyone has the patient to invest and wait for a very long time and investing with the DCA or Lump sum method you do not need too many analysis or information rather just ensure to keep your reserve and emergency funds and have a good management skill you are good to go...
One thing you need to understand is that their is no short term investor as you claimed, it's either you are Bitcoin investor that buy and hold for a very long time or you are a trader that buys and sells for minimal gains which have no significant effect on your finances, so those people that called themselves investors that sell at every price increments is nothing but a trader not an investor.
Because the way Bitcoin is wired, it's best to buy and hold for a very long time in other to reap the full dividend of your investment, not selling prematurely as they usually does.