GRIN is a serious project
For your information, every projects (crypto project) that exists, consider themselves serious project. Even the community of that projects considers it serious project or they would not spend their time. It's the saying and motivation that drives the community but ultimately in the long run, the project which can keep the community together and spread wider - becomes the successful project and can eventually establish that they are serious project. Just by telling or assuming that "we" are serious project, does not make a project serious and successful.
When I talk about seriousness, although I understand that it may not mean much, I was mainly referring to the fact that there is development is fully community-driven and decentralized, with no ICO or pre-mining, promoting true network autonomy.