A smaller meeting provides a more intimate environment for greater interaction among participants. Sessions are geared more towards interactive discussions rather than lectures.
We have distinct characteristics: we are more spread out than our colleagues on the East coast creating more isolation; we have somewhat different institutions, etc. Meetings enhance networking.
By acting as a block, we may be able to develop closer ties to federal funding agencies, and to create greater leverage with our instrument and consumable vendors.
Lower travel and meeting expenses.