Merriam-Webster lists two definitions for the noun 'creative':
one who is creative; especially: one involved in the creation of
creative activity or the material produced by it
especially in advertising
The lack of an article in your phrase, which would appear before 'creative' when used for one person, indicates that the word is used in the second sense.
As many have pointed out in comments, this is lingo (jargon) used primarily in the fields of marketing and advertising. Given M-W's definitions (and notation of first use in 1962) it may well have developed as a truncation of 'creative department' within an advertising agency.
In online advertising and web production, where I worked back in the 90s, the preferred term was/is 'content', a word that could easily be substituted for 'creative' in your sentence.
Many in digital talk about email almost as [if] it were analogue (tired and old hat). But few underestimate its power when combined with CRM, automation and great [content.]