Hey there! I was in a similar boat to you a few years ago and couldn't decide between Law and Commerce, I couldn't see what I'd be doing for work after uni also, so I decided to do both and see where it could take me. I'm currently in second year
I think doing both Laws/Science or Laws/Biomed is a really great idea if both of them are of interest to you. I'll list some *potential* pros or cons of studying Law + Science/Biomed for you.
Pros• You'll get to study two degrees in fields that are of your interest
• You'll come out with two very highly regarded degrees
• Limitless career opportunities with a Law degree (you don't necessarily have to go on to be a lawyer or work in a law firm)
• Opportunity to get into Doctor of Medicine @ Monash - which is exclusive to those who studied their under-grad at Monash (75% of places reserved for Biomed students)
• You can drop either of the degrees if they are not to your liking
Cons• More Law units than Science/Biomed units (could be a pro, depends on what you rather)
• You will most likely finish your Science/Biomed units before your Law units, meaning you will have a time in Uni where you are studying just Law on its on (could also be a pro again?)
• Law tacks on an extra two years of studying, where as Science or Biomed will take three years to do alone
• Typically two of the most challenging degrees
• I hear Biomed is really competitive as many students studying it want to get into Med
Feel free to correct me on any of those points
And there is most certainly benefits to doing both degrees, personally I wouldn't say either are a waste of time. However Biomed is generally studied by students who are hoping to pursue careers in the Medical field. I'm not too familiar with graduate career opportunities for Biomed apart from going into Doctor of Medicine (or another type of post-grad med) or Scientific research, but I do know graduate career opportunities with a Law degree are limitless!
I hope this helped, feel free to ask me any questions! Best of luck with your studies