Surely i don't think if there is any place that was stated that buying bitcoin through DCA is the only recommended strategy in buying bitcoin or investing in bitcoin. although buying bitcoin through DCA is one of the most reliable way of buying bitcoin compared to other form of investment strategy, but doesnt mean others are not useful. or the two others are not recommended. i find the word "ONLY" to be problematic, in terms of your description. we should not neglect buying the dip and of course lump sum, as all will make a good or better investment
You are right but the reason why folks usually recommend DCAing is because is more reliable when it comes to purchasing bitcoin, the other strategies such as Buying the Dip and lump-summing are also good , but not as reliable as DCAing, like for instance buying the dip one have to wait and most time doing the waiting we may endup missing out, while in lump-summing is not everyone that have enough funds to execute a nice lump-sum purchases.
Like for me using the three strategies if it's convenient for yer is nice , but using both buying the dip and DCAing is just the best , because you don't have to wait for the price to dip first while using DCAing method, so you can easily save some money as a reserve funds to buy the dip whenever there's any , without one waiting for the price to dip first .