Always research the company behind these things . . .
Obelisk is a subsidiary of Nebulous Inc, which is the company behind the SIA blockchain development. Nebulous is a company based in the US and you can actually identify and name its owners and the people behind it. If it goes south, their reputation is on the line as well as the US legal system being brought to bear on them. They have also been quite open about what they are doing and where their funding comes from.
A few links for your reading:
https://blog.sia.tech/https://sia.tech/funding2016/https://siawiki.tech/development/nebulous_incHow can anyone be sure that these are real? That this is not a scam?