Actually, this specific example usage of "actually" could have a meaning. It depends.

"The body of the template is parsed, but, contrary to popular belief, not actually type-checked until the template is used."

One can omit the "contrary to popular belief", but the "actually" would still need to stay, as it hints at the "contrary to popular belief".

It's not as simple as "it's not needed there".

The lack of recognition of perceived Noise as an actual part of the Signal, eventually destroys the Signal.