I don’t believe Astralis using 6th and 7th players has any benefit in the actual game; using one of them in a tournament will only make the team worse, so why would Astralis sign them? There are a number of theories out there, but here’s my best guess at it:
They sign these players who are in free agency and use them in lesser tournaments. The first purpose this serves is in allowing a player to have a break if needed. The main purpose, however, is to use them as part of their system and make that player look like top-tier talent, contributing to a winning team’s success.
This essentially takes a player that they signed for free and turns that player into something they can sell to one of the other Danish or international rosters. If Astralis can still make deep runs in an event with es3tag or JUGi playing on the roster, then other teams will see those players as being capable of achieving high-level results.
So my theory is that they will prop these players up, using them in their system with their support staff and everything that comes with it, increasing their value only to be sold off to one of the other Danish rosters. To be fair, these players will probably develop and get better as a result of this, but they will more than likely look better than they actually are.
This also makes sense in light of recent announcements that the Astralis Group asked their staff to take pay-cuts. This is an opportunity for the company to add another possible revenue stream.
Astralis adding 6th and 7th players to their roster could be serving more than one purpose, too, using them to give players a break, as well as potential financial gain by selling them off. This is just pure speculation though; who knows, maybe they are trying to revolutionize the way the game is played. I don’t think they are, though, I think they know better than anyone that introducing an extra player is not going to have any benefit in the server.
