My experiences with work coaches is that they change so regularly that I haven't been given the chance to build up a proper relationship with them, so they've not been able to tailor my work needs to match my circumstances.
I also often feel that they are rushed between appointments, and therefore often don't even have enough time to read your background notes in your work history before seeing you.
I have been threatened with sanctions by them before, and was so worried about the consequences that it would have had on me and my family.