Different people have different strategies in terms of investment and everybody have a particular strategy that work for them.
Buying Bitcoin by DCA does not necessary mean that the investor have limited capital, most people that buy Bitcoin by DCA still have the capital for lump sum but one of the reason why some people prefer DCA to lump sum is that some people see lump sum as a method that is risky because of the volatile nature of Bitcoin which they cannot possible tell what the price may be in the future. So to avoid any uncertainty in regard to dip they see DCA as precautionary way of buying Bitcoin than lump sum which requires buying Bitcoin at once with the capital at hand without considering whether the price will dip or not.
Buddy yea people decide to chose whatever strategy they are comfortable with but in all many people still prefer DCA method no doubt, I don't understand what you mean by lump sum being risky because of volatility, mate volatility is Bitcoin thing and I believe that an interested and a ready investor that understand the concept of Bitcoin will not want to buy with a lump sum amount just because of volatility I don't think you're right in this one, even though such person decide not but in lump sum does that stop volatility, volatility favour both upsurge and dip but that wouldn't deter anyone from buying in a lump sum if they have the lump sum amount ready at anytime.
If thats the case people would've not been considering buying in a lump sum since the aren't aware of what happens in the future in regards to volatility, buddy thats a no no bro, Bitcoin can not stop being volatile and as a matter of fact i think it's even the main reason it's what it has become today and anyone seeing such as being risky doesn't understand what Bitcoin investment is. Bitcoin has a good future, that shouldn't be doubted, at least with the recent events everyone should be certain about Bitcoin asset in the future so mate if you have a lump sum amount at anytime buy, don't be discouraged because of volatility because no matter what happens if you hodl for a long-term what we are experiencing now will happen again and if you endure for a longtime without shivering on the different market experience then you will benefit.
As for DCA method it's very efficient and less stressful method of investing in Bitcoin, it helps all category of investors to be part of Bitcoin investment, with this method you can invest with any amount but what matter is your consistency and steadily doing the needful to remain relevant in the said investment and hodl for a long-term.