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