Because "Technical Consultant" is associated too strongly with the old-school consulting firms, and the new crop of companies selling into enterprises want a cool new title.

It also riffs on military terminology which, for better or worse, is "in" right now..

I'd guess it's popularized by Palantir which did the FDE model on a large scale (to great success) though it seems now the competitive landscape for AI implementation is broadening (such as openai implementation partners for ex)

Why did we invent the term Data Scientist a decade or so ago to replace Business Analyst?

To try and give the position a rebrand with more prestige and hire better people for it.

Mo said to and people listened [1]

[1] - https://www.youtube.com/watch?v=juHv_Vi4giU