Running candidates is primarily a vehicle for propagandizing and building the party, not for actually winning. A PSL candidate (they run as Peace & Freedom Party in California) hasn't ever come close to winning.

I think it also helps the PFP maintain ballot access and build their registered voter rolls which might come in handy some day and is an important tool to have.

I think the CA PFP/PSL slate (Vote Socialist CA) is interesting primarily because of some of the lower offices that could potentially actually be won. The slate is also running candidates for State Superintendent of Education, Insurance Commissioner, and Controller, races that a lot of people don't pay attention to. Since CA has a non-partisan top two primary system, just getting second place in some of these smaller races gives them a good shot to win the general, as well as plenty of media coverage in the process.

And if any of these candidates were to win, they are all cadre members of the PSL and beholden to the party line.