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.
Liquidity or not I will not advise any newbie to venture into trading immediately but should take the time rather to be stashing some bitcoin for a long time plan as it's going to pay off than trading would in the long run. I have been there and I know how stressful and tasking trading could be and that's why we have large percentage of losers in trading than profit makers. Whereas in bitcoin investment just as you have said you just have to keep stashing either buying at a low or use the DCA approach and hodl and cast your mind on other real life activities while your investment reap you profit with time. The important aspect of it all is that when investing in bitcoin you don't just lose except you panic out of market FUD and sell at a premature period.