The dude is not totally wrong neither is the dude totally correct, DCAing weekly will make an investor grow their portfolio faster than someone that is investing monthly but the things is that it depends on the amount these investors are using to invest so if someone is using DCA method for weekly and they are not consistent or they are not using a good amount to invest someone that is investing monthly will grow their portfolio more if they are using a good amount than someone who is investing weekly. But whether investing with good amount or not the most important is to just start.
The most important thing is to stick to your plan, whether you do weekly or monthly. The DCA is more about how constantly you accumulate and the amount you put in. It is true that a person who uses weekly and not consistent with the accumulation or use a small amount to invest, at the end, they may end up with a small Bitcoin holding than someone who invest big amount every month. The DCA methods does not guarantee success but it depends on how we use it.
But I also agree with your last statement, the best thing is to start. In the end, those who start and continue buying will see results, but many people are wasting too much time thinking about weekly or monthly, perhaps waiting for the dip to buy. Bitcoin history makes it clear that those with long term plans have a good return.