A commute is, by definition, travel between one's home and workplace. Your home and workplace are the same, so I doubt you incur any public transit expenses worthy of commuter benefits. A commute does not include workplace errands or travel to locations you'd prefer to work from (if anything, your employer might reimburse you for work-related travel expenses). You could probably make a case for using it to travel to co-working spaces provided by your employer.

But as many people have pointed out, enforcement is an extremely unlikely possibility. And worst case, they're just going to ask you to pay taxes on the benefit. So if you are willing to take that risk, just sign up for/use the benefit.