It's a valuble concept. I think both definitions contain elements of what makes something a platform. It implies that there's something below that isn't raised. Maybe what's below is very rough and uneven, and the service provided by the platform is to simplify or flatten the concepts to make it easier to work with. I think so.
Platforms build on platforms.
More like those 3D chess games they play on Star Trek. Elegant, but a bit of a klooge. Not a political one, but a celebration party. If I'm the only partygoer, it's not much of a platform. I want dancing, singing and lovemaking at my celebrations.