How about your stop loss?
I think this method is also just like trading. Although, this is kinda risky for now these days, since we are still near from recent all-time-high but if the percentage of loss from all-time-high is kinda last 2019-2020 year, this method is useful since we saw a lot of dip before.
But I am not telling Bitcoin will not reach new all-time-high again, I am still bearish for Bitcoin now.
There is no need for stop-loss. OP is simply buying, not (margin) trading. Yet, the suggested method will work now in a bull market but fail badly in a bear market like the end of 2018 and the whole of 2019.
I'm in a bearish mood now too.