IATSE Local 480 is what is referred-to as a Studio Mechanics local, which means that we cover myriad below-the-line positions (albeit a very specific list) within the film & TV industry. Other locals cover crafts such as stagehands and broadcast technicians. If you’re looking for that type of work, you’ll need to find the IATSE local which has jurisdiction for crafts of those types.
Some crafts aren’t covered by a union at all. PAs, or Production Assistants, are a great example of a craft that is not covered under any union contract. If PA work is what you seek, being a member of the local will not benefit you.
Local 480 does not cover actors of any variety. If you work as any type of actor and are looking for union representation, you may be interested in joining the Screen Actors Guild (SAG).
Since Local 480 doesn’t specifically find work for its members, you should be confident that you will be able to get hired on a consistent basis before you join the union. It’s very similar to an old adage — “It’s not what you know or who you know, but who knows you and wants to hire you.”