Hi and welcome to bitcointalk forum!
By other "offline currencies", I guess that you mean to gold and cash, let me explain why bitcoin is better then them.
Cash- Huge inflation, which means that if you hold cash as a store of value, at the long run you will lose value!, can be only transferred by a face to face meeting(someone need to physically deliver the cash to you).
Gold-Hard to store( takes a lot of space and may require to have a security behind), and also hard to transfer
Bitcoin- Fixed inflation, which means that you won't lose value at the long run, and also very easy to transfer,you don't need to actually meet someone in order to transfer bitcoins and you can do it from home.
Also it's value goes up at the long run.
I agree with everything you said, however, if we are to look at them, cash will still win for now only because it is used by a lot more people. Sure, there are people who are also using gold and bitcoins, but it is only a small fraction compared to those who use cash. So while bitcoin is superior than cash (and gold), people may support it more because it is tangible and has been around for centuries.