Buying Tokens with no working product, hoping it will rise, when the hype is over, is not a good long term strategy.
Just buy the Token, when you need and use them.
99% of the market has no working product yet. What i do is spread out my investments and use a little bit of TA to plot out when is a good time to stock up, as well as dollar cost averaging (which is a great investing technique).
If you've done your research and you believe in the project then there's no reason to not invest a little in it while the project is still in early development stages. By the time they have a working product, it will already be too late to get a decent share of the market at a good price.