The old choices were: hire a senior operator in-house, hire an agency to run a slice of it, or hire a consultancy to write a strategy you implement yourself. All three break down once you grow past the founder's lap and below the C-suite line.
Fractional partnership is the third path. You get an operator who is accountable to the outcome, embedded in the team, with a fixed cadence and a fixed scope. They build, run, and hand it back when it runs itself.
It's the only model where the incentive is to make yourself unnecessary on a known timeline — and that incentive is what makes it work.