There are several reason someone might want to spread the investment over several weeks or months as the case may be and it is usually a case of personal preference. One notable reason I can come up with is to get filled at different price point which may result in collecting more Bitcoin with the same dollar amount. For instance, in a market that is generally in down trend, dividing the funds and spreading the investment will make you get some coins at lower prices which will result in more Bitcoins. The reverse might be the case for a market that is generally in uptrend and this comes back to personal preference even though the overall goal is to be optimally invested in Bitcoin.
I don't see much difference between monthly and weekly DCA, and the choice for which to use depends on the cashflow. For those earning monthly income like salary, going for monthly DCA is best so that as soon as the funds are received, the part for investment are immediately converted to Bitcoin and transferred to a safe wallet. On the other hand those running business and seeing money daily can go with the weekly DCA as this may resonate more with them such that at the end of the week when they balance their books, they can easily set aside the funds for their Bitcoin investment. So the cashflow play important role but there could be other factors too that may inform the choice and investor will use.
If you receive salary monthly and you think by dividing the money you have set aside for your Bitcoin accumulation into weeks will earn you more Bitcoin through the hope that there will be a dip within the week were you can buy at low price then you are just a trader.
Have you thought of you dividing it and in the course of you buying weekly with the money met for the month and Bitcoin price goes up will you wait for it to come down before you buy or you will still go ahead and buy, there's no need dividing it if you receives your salary monthly because there's no difference in the monthly and weekly accumulation except you are a trader who is waiting for a dip to happen.
This is not the definition of trading. The post is simply addressing different ways one can go about accumulating Bitcoin and hodl and not necessarily how to sell. As much as it does not involve buying to sell in a short time, then trading is out of the picture. Traders mostly do not use the DCA method but prefer other technical analysis method that will make them think they can catch the both in a bid to buy low and sell high. This is different from when an investor adopt any method of buying Bitcoin to hold for several years.
It is also important to note that the method of buying Bitcoin have little effect on the success of the investment, rather how the investment is managed is the key. Despite the entry method, as long as the investment is held across several years, there are good chances that the investment will be more successful and someone that buy to sell in a short time and probably at the sight of profits.
So let us not argue too much one what might be the best approach of buying Bitcoin rather let the focus be on what should be the best way to hold and also resist the urge to sell in a hurry.