The data, though, is a physical thing that must be stored. The information transmitted by the data is a physical thing--either soundwaves, or images, or whatever.
No.
By definition, information is not physical. It is not a physical thing.
Data can be represented by a physical thing (like the grooves on a record) and data can itself represent a physical thing (musical data represents the amplitudes of physical soundwaves). But that does not mean data itself is a physical thing - those are just the conceptual links between physical things and data.
Think of it this way - can you point to raw data and say "This is data?" No.
I can point you to a chair and say "That is a chair." But I can't point to data and say "That is data." I can only point to a CD and say "That contains data, but is itself not data" or a movie on a screen and say "That is a movie, and is represented by data, but it is itself not data."
It's a subtle distinction, but an important one, which is why it has its own branch of law.
Things only have an existence when perceived
That's not true. Things can exist without being perceived (the aforementioned chair exists in a dark closet, even if the door to the closet is closed and we can't see or perceive it).
Similarly, ideas can "exist" without being perceived. They exist in our heads. If they didn't exist, we couldn't think about them or discuss them.
They are not tangible or physical, but being physical is not necessary for something to exist.
You could be right that there is a legal distinction, but I don't necessarily think there should be
So if you buy a DVD and it later gets scratched, do you think that you should have to buy a brand new one, at full price?
Or if you have a VHS tape but don't have a VCR anymore, do you think you shouldn't be allowed to copy the VHS to a DVD so you can watch it on your DVD player (assuming you paid for the machine that does the conversion)?
These things can only make sense, legally, if the distinction between IP/data and physical objects is legally made.