Does help yourself can be a greeting?

[Aaron]

A friend of mine who's not a native English speaker just sent me a message like this.

"Help yourself and have a good day, honey"

I know help yourself could mean make somebody feel comfortable when there's a food. <- a food? just foods?, but I wonder if "help yourself" could mean greeting like above sentence.

Thank you.

[Aaron]

I'm sorry. I don't know why nobody answers me. I wonder if my question was too obvious. Although it is obvious, It's difficult to me. Please help me out.

Thanks.

[Aaron]

Please~ answer me. T_T

[Casiopea]

"Help yourself and have a good day, honey"

Sounds like a closing to an email, not an opening. "Help yourself" is in answer to a request, and the request doesn't have to be about food. For example,

A: Can I borrow some DVDs?
B: Help yourself. Feel free to take whatever you want.

A: Are these books on sale?
B: No. They're free. Help yourself.

A: Do you have a tissue?
B: There's a box on my desk over there. Help youself.

[Aaron]

Thank you so much. That was really helpful and I totally understood now.

[Casiopea]

You're welcome.