There is a big difference but the biggest one is actually you get to work with more altcoins and in investment you only work with the coins you have invested in with trading you need to check everything and every coin which is the best for you.
There is really a big difference between trading and investment. Oh no I dont think trading can give you a lot of money more than investment cause investment is what you invest on knowing that you can earn a certain rate. But for trading, you can end up losing your money, in fact, some novice end up losing all their money. Some people start trading, and after trading for some years, during the time calculation they find out that they actually made nothing money spent becomes larger than what was invested.
Investment is something that you can invest your money in some project like people are investing in ICOs and then earning money from their ICOs while trading is just simple buying and selling some thing when the rate is varying.