The virtual column feature I remember is halfway in between. It is not part of the DDL nor reported table schema, so the developer needs to know about it.

But if a function called silly with input type my_table existed, you could still do your second query. It has syntactic sugar for making a bare function name implicitly invoke on the current row record.

I can't remember if that sugar could also be used in an expression index. I never really used this syntactic feature, as I thought being more explicit with function calls would be better coding style.