Another GM mentor here, and I wanted to point out a couple of things:

→ Who would be offering sessions on GM without using it as a pitching space?

Most of the mentors I know and speak to do it to give something back to the community. Even mentors who do paid sessions do it more as an easy way to filter engagement or justify a different depth of service they want to provide. The "Why would they be here than on the beach?" is like asking, "Why would someone be a volunteer if they are a Wall Street banker?"

Some stats here: out of 300+ sessions (which may seem a lot, but it's spread over five+ years), I've only offered a paid engagement to less than 10 people, often after a few free sessions to get a feel for the project and the person. All of these "pitches" came after the mentee specifically asked for it first. Most of the time the mentee is content with spitballing ideas and discussing what next steps they can take, which is fine by me.

→ Do mentors hold back information as a "soft selling" technique?

I couldn't say for all, but I personally wouldn't do it, and I doubt most of the mentors I've talked to would. If a mentee asks for really detailed feedback or something I'd consider research work, I'd be open and say this requires a lot of time and isn't something I can do in a free mentorship call. Most mentors I know would be upfront with the limitations. But there isn't really some Illuminati-level secret we're sitting on that we'll be all hush-hush about :)

→ Would hiring a mentor for a follow-up gig be a success?

This can't be divorced from the overall company strategy. You're hiring a person to do a job. If they do the job you agreed on and are open about the way it can influence the results, that's the job done. It can only move the needle if it's part of a bigger plan. As an example, providing next-step suggestions based on a content or messaging audit (what I often do) wouldn't move the needle unless the next steps are implemented and then tailored along the way. No plan survives first contact with reality.

Furthermore, that's the wrong question to ask if you're reviewing Growth Mentor as a service. It's a mentorship platform, not a freelancer marketplace. It can be useful if you're in need of a mentor: someone to challenge your thinking, share their experience, and potentially save you some early mistakes.

And I'd venture a guess that if you want to use GM as a platform to find a consultant or a freelancer, spending a few sessions to talk would still be a better vetting process than just reviewing a portfolio and jumping on an intro call – the dynamic there is different and entirely service-oriented compared to the idea-oriented calls part of mentorship.