What is most important is the number of Spellbooks purchased. These are players who have been converted to become investors in @splinterlands.
Anyone, who bought a card or a card pack can be seen as an investor. I bought the Beta starter set on 2018.12.30. I am a player too. Probably most of the investors are players too. With encouraging to play/keep playing, there would be more active players. The recent changes in the reward system with the Glint is a good step in this direction.
Good luck and have fun.