Better do a long term investment for it is more safer for those who currently starting a career in trading. In long term, it is more simple, you are going to buy a btc and hold it and wait until it rise and sell it to the best profit that you can have.
To me I think that both day trading as well as long term investment is good for making money, but in fact it is depending on ones experience and interest. I think that day trading require a lot of hard work and study, while in long term investment you only have to wait for the good time and when the price increases too much then you can get good profit from there.