In Mahematica any keyword can be used as an unbound variable. So you need a way to disambiguate f(x) meaning f multiplied by x vs. f[x] meaning f applied to x.

In Mahematica any keyword can be used as an unbound variable. So you need a way to disambiguate f(x) meaning f multiplied by x vs. f[x] meaning f applied to x. If you use parentheses for both you'd have to give up the ability to express multiplication as a(b) which would be a bigger loss I think.