This Treasury Proposal was to fund the Society account with 1000 KSM
The significant majority of funds in the Society account are used to pay for bids from new bidders - previously the only balance in the society was there due to donations.
With 1000 KSM, a bid of up to that much may be accepted by the society, increasing the potential draw of bidding to join the society. If membership increases, society members can plausibly make a strong marketing force for Kusama as a whole.