If you've got spare money to invest into these platforms, it's okay to do so but always remember that you're passing on your funds to them and you'll no longer have any control on it.
I am not telling not to invest but to invest what you can afford and definitely understand that risk upon doing it. Well, if they've got some marketing again in the future, for sure that it will add more popularity to them.
It really depends on your trust in the company you're investing and trust is built up when you see that the platform has a good reputation in the industry where they are in.
There's really no safe investment, so even if the platform looks safe and reputable, the experts' advice to only invest what you can afford to lose applies.
They already mention marketing here in the future, but they already have marketing elsewhere in place.