Yes exactly, with the DCAing method you can start from investing a smaller amount then you keep on maintaining the standard amount and sooner you might get another opportunity which might make you increasingly increase the amount which you allocated to your investment (from investing $15 to investing $20 or $30 in Bitcoin) and other things are it doesn't matter how much you put monthly what matter is how consistent you keep on buying. When you bitcoin of $30 every month a year is =$360 and during the year there might be a month when you will allocate more than $30 that's why you have to keep on buying so you can meet up.
DCA helps you to be more realistic than being more speculative. You don’t get to wait on a right time or even need to look at the charts to get an over view of what is been done or what your to expect of the market. You simply set your limit price and the volume you which to buy in BTC or it’s USDT or equivalent in whatever coin you’ve got values in, that’s in the event you ain’t buying with your credit card, Bitcoin ATM and whatever means available to you.
It’s more of a safe means for someone who isn’t entirely sure on what to do or how to approach the market and even still, those whom are sure but just can’t take a pause on building their portfolio. You always get there eventually and that’s a fact.