That is better, because if he starts saving money to reach a big amount before buying, he will not be able to have a good bitcoin size in 10yrs time compared to when he starts putting the money that he is saving in fiat into bitcoin. Imagine that you have a ten years bitcoin investment plan and you used one year to pile up $2600 which you have being saving $50 weekly, and he used that money to lump sum the next year. Imagine that if he didn't wait to pile up that money and he started right away, he has the advantage to buy bitcoin at different price level every week at $50 through DCA. In one year time he would have accumulated more that $2600 worth of bitcoin, because he bought right away and might even buy at a more cheaper price compared to the guy was was saving his money before buying.
The guy that saved his money might not be able to buy with all his $2600 because there might be some challenges that will come around that will make him use part of the money that he is saving to buy bitcoin. Another thing is that what if bitcoin price is very high during when he has gotten the bulk money, will he start waiting for the dip before buying, he will miss a lot of buying opportunities in the market within that one year that he was busy piling up fiat. Fiat depreciates, so it is better to start keeping the value of your money in bitcoin. I just used one 1 year for for my explaining, to give a fast understanding. Bitcoin investment should be on a long-term goal and start right away because time waits for no one, bitcoin price increases as time passes on and waits for nobody.
I personally, I have two sources of income so what I do is that I leave one part of my income in Fiat just to take care of some real life expenditures and the other part of my income to accumulate bitcoin using the DCA so it makes me to feel so relaxed because i know nothing will interfere between the money am using to DCA because i already have Fiat to attend to any of my needs so starting up an investment doesn't mean you should have a huge amount of money before making a step and if you even have that mentality of saving a huge amount before you buy Bitcoin, it's either you will buy at a high price when you could have bought at a low price if you started accumulating by DCA or you can even lose interest not to buy if you discover that the price is very high because you will now consider the price when you started accumulating Fiat to buy Bitcoin and the price when you finally gotten the amount you want to start with so it may discourage you not to even start at all and you could even begin to reason about investing on real life projects thereby your aim to accumulate Bitcoin will be halted.
Accumulating little by little using the DCA is a sure way to own a huge portfolio. Most people who own huge portfolio today started very little and now they are proud they took the bold step. There are times when we feel that our investments is too little but by consistency the investment begins to grow with time but if you decide to meet a target before you start accumulating, you may end up with nothing or not accumulating at all.