I like that the fees for buying small amounts of currency are so low compared to if you trade stocks. It's nice having a % based fee instead of a flat commission which can really eat up a percentage of your profit if you're trading with less than $1,000.
I'm doing what you've mentioned here--buying small amounts over time and diversifying into 8-10 different coins that I plan to hold for a long time.
The only short term trading I've done in cryptos is when I bought the bitcoin breakout above $3k and then exchanged it for other coins once it hit about 10% profit. It only took a couple of days.