Given that the VCE Plus scheme is basically the same thing as completing a university level subject whilst in Year 12, it would be no secret that the workload is intense. An obvious benefit would be having the opportunity to experience how a university subject is operated - and how La Trobe in particular operates its law department (as you may think about going there next year).
An obvious con is workload. I've never experienced a law subject at La Trobe, but if it is anything like other subjects, the workload will be high. Lectures are usually recorded, so if you can't attend make sure you watch it on Echo 360. Do they give you access to La Trobe's LMS or not as a VCE Plus student (I assume they would for your subject's online resources)?
Make sure you ask someone if the lectures are recorded, and definitely attend the tutorial.