This is probably just a semantic difference. In the marketing/advertising industry, “advertising” tends to refer to a subset of channels (banner ads, social media ads, video ads, TV ads, billboards, etc.) while “marketing” refers to the general problem of getting the word out.

I think you’re using “advertising” the way a marketing person would use “marketing”.

I don't think this changes anyone's point, just clarifying what might feel pedantic where there is a term of art associated.