That strategy requires you to have good timing on the market. But the problem is, by doing so, it will make you emotional and you will be prone to make mistakes making you lose some of your money.
If you want the best strategy for ordinary investors like us, "buy the dips". If you have a job you should save 20% of your monthly salary and make that available to buy when Bitcoin's price is falling.
As I always suggest on people they should just hold their bitcoins because I am sure that as time goes by the price is increasing the value is increasing so you just need to hold onto yoir bitcoins for a long time and it will be more beneficial to you