This does make a lot of sense; I don't think there is anything wrong with starting from what you want to earn from your work, then working backwards. If you aren't able to charge that amount yet, then at least you have a target to support an income that supports your lifestyle.
It's a rather weird culture and the fact that we are all dumb..!
It only help companies keep the rates low and avoid the inflation raise.
If people could share their rate and tell why (experience, years, skills, etc) then other could see if they are either too low or too high and adjust.
Here in LA, the Burbank Animation Guild has every 6 months (or so) a wage list for each position.
By the way, do people realize that many producers like to share Excel files with the rates of freelancers and other "notes"?
It's easier to put a monetary value on "time," thus what is your projected annual salary, than something intangible like skill. Besides, as your skill level increases your time would become more valuable so in essence you have that scale in this tool. It's just a different way of thinking about it.
I think this tool would have been more helpful if it was more about skills and expertise versus "how much do you want to make." For instance: How many years of experience do you have with After Effects? Are you a student? Maybe a sliding scale of comfort and expertise with Cel, 2D, 3D, Houdini, etc, which would then give a rough range for a daily rate similar to Joey Korenman's book. I know not all "expertise" is the same, so I'm sure this would be a bit of a challenge to nail down a dollar amount based on that, but just a thought.
What I love about this tool is that it makes you think about other factors besides just the salary - it gives you ideas about time off, bonuses, etc, which I don't think about often enough as a freelancer.
From my experience, it can be difficult even among close animation/freelance friends to be really frank about rates (myself included). So until cultural norms catch up, this is a fantastic tool.