Reasons for your consideration:
- The primary current meaning of the tilde is "approximately equal to", which is analogous to the definition of money.
- The squiggly line of the tilde is similar to the vertical or horizontal bar common to currency symbols, but more ethereal to represent a digital transaction.
- The tilde is easily accessible on any keyboard. I'm writing this on my phone.
- The tilde is easy to draw by hand.
I don't know, I have become so used to dealing with tons of zeroes that for me is not a problem anymore to work only in terms of BTC. I understand this can be a pain in the ass for noobs tho.