Nothing good can be achieved without holding in the long term. If you do something in the short term, it becomes trading. If you do something in the short term, you cannot gain much from it. If I have done these or am still doing some things, from my own analysis, I can see that if you do something in the short term, you cannot expect anything good from it. However, some profits can be achieved but not much can be expected.
Dude, it is not always a must to hold for a long term. Not every one who hold all their coins for a long term, some of the coins may be for a short term holding. Each person may have a different strategy, we can't expect everyone to hold for a long term.
By the way, holding for a short term will also gain good profits. But it is probably lower than the profits of the long term holding. If you use a big capital, it is not impossible to gain bigger profits, too. However, you must be professional traders/investors if you want to use a big capital. It is because you must deal with chance or risk of losing big amount of money as well.
If you can maintain DCA and invest in the long term with understanding, then it is best. It is true that to get something good, you must have the mentality of holding for a long time.
DCA is a good strategy in investment. In this way, we can collect good number of coins although we have limited funds. Sure, we also need to have strong mentality because we will face many FUDs or bad news many times. We will also see many corrections during we hold the coins for a long run.