It is assumed that with trading you can make profit faster than you will do with investing by buying bitcoin either at a lump-sum or with the DCA approach and hold for a long period of years before making profit.
This is not as easy as they say, trading is risky and one should consider their equity/liquidation level before doing that. What if the liquidity is not high? That account will certainly be put to trouble. But in investing, no matter how little or much you have, your Bitcoin will remain your Bitcoin and if it drops so low, one day, it will get back to your striking price and even edge it higher for you to make money without the risk of liquidation.
Also, every investment approach is good for Bitcoin, you may buy low, DCA etc, what matters is for you not to miss out on the slice of the world cake.