Hosts are giving tokens away in order to promote their projects.
By distributing tokens, they can reward their users or try and attract new users by distributing tokens to individuals they suspect would be aligned with their projects vision if only they were made aware of its existence.
With Vesting Party in particular, these promotional token distributions may be subject to vesting restrictions which prevent them from being sold immediately. So a Host might also expect the people they invite will be more likely to independently take actions which help the project succeed, since now all the people they invited will have a vested interest in their projects success.
Just like in real life, the best way to get invited to parties, is to interact with people and communities. Often communities will host parties and send invites to people who have interacted with their projects, or with projects associated with other communties that they feel aligned with.
If you are participating in a community that might benefit from hosting a party, you can also help educate and encourage them to do so!
The Vesting Party Token (VPT) is used for community governance of the Vesting Party platform and to align the interests of the platform and its community with that of its users.
When someone hosts a party on the platform, a percent of the tokens they distribute are awarded to the Vesting Party community, as those tokens vest, half of them will be automatically exchanged for VPT and used to provide liquidity between the users token and VPT. Therefore as more tokens are distributed through the platform, and those tokens appreciate in value, VPT will appreciate right along with them coupling the success of the Vesting Party community with the success of our users.