I've got a millions of reasons why you're strategy sucks.
But I will point out the major 2:

1) Diversification

Diversification is a key concept in asset management and specially in the financial markets. Basically, let's you take advantadge of volatility (and in alts is very high!)

2) Risk Management

Buying large amounts of a certain coin at a particular time is a huge mistake. Pick a money management system (antimartingale or antimartingale depending on when you increase your sizing position) and follow it. I suggest anti martingale money management. In trend assets, works great and allows exponential growth of the returns.