Facebook's cryptocurrency Libra is a stable coin so even you have a lot of libra in your wallet, it will still be the same value even after a lot of years has passed by. It is only good for making purchases online but if you wanted a long term store of value then you will still go back to bitcoin or other cryptocurrency because they are the ones who are only can go up in value which gives you profit.
If ever I can see it that it will be worth to use and I can see that it is user friendly, then why not, will be able to use it if possible for as long as the fee is not too high and my country is not restricted to use it, but with regards to investing I doubt and I know that I will not invest on it as it will be not worth it for me to invest in this kind of thing as I know that it is stable.