The custom character is just stored at the custom character location. On screen appears a 'copy' of that, not the character itself, if you understand what I mean.

So, you can creat up to 8 characters, store them at their place, and then display that character to the location you want, as many times you want. The LCD just copies the custom character to the location on-screen you specify. Isn't this the same when you display e.g. "AAAAA"?

But remember, when you power off, all are gone. You have to reload the characters on power up.

Ioannis