I’d have misgivings, it sounds to me like officially bureaucratised micromanagement and bullying.
I pick on this but there are several others I could have used as the example. But really?
I have mentored and mentee’d.
First and foremost you need to ensure that you get on with your mentor / mentee relationship, I’ve found it works best if you are not in the same work area. Then you can be honest about issues you/they are facing without necessarily the mentor having any control or influence over the issues specifically. I’ve asked in the past if they want any intervention by me and generally the answer is no, they just want some advice how to handle – sometimes procedures, often politics.
It can be really helpful particularly for people finding their way in the organisation; navigating ‘how to do things round here’, particular styles, etc. Also for people progressing up the ladder, helping them for that next role / to settle into that role. I don’t believe in vanilla-ising yourself totally to fit in, but if you rub everyone up the wrong way in the modern workplace it doesn’t matter how good you are at your job, it will not be appreciated.
Yes, there are pitfalls and if the mentor is only there to then grass you up to your line manager then it would be misused, but done properly can be very useful. I have certainly benefited.
As suggested above, all the email needs to say is that you’d like a chat, and then take it from there.