Another thing to add on the adding value front:
My role is in data protection. I've specialised in this for a long time, and I'm pretty damn good at my job.
But there's no reason that my company would know that a) I'm shithot at data entry and b) I actually kind of enjoy the race of "how many can I enter accurately and can I come up with a UI efficiency to improve the process".
It's not mentioned on my CV that I absolutely BLASTED through work like that. That I could complete nearly double the work of my nearest colleague. Because my CV is tailored to the role, and the role is to be available to deal with compliance matters when they arise. Not to hammer through lightweight admin work.
(I very much enjoyed turning up to do admin work whilst still getting paid the fact salary too! Was kind of annoyed that I developed the processes well enough for the rest of the team to mange without me.)
In a company of 350 people, the path to them finding out what else I can do is quite hard.
In my small, lean company, we did personality and work behaviour analysis and people could reflect, stick their hands up because they knew the sort of work that was available, see when someone was snowed under etc
I wouldn't know who was snowed under where I could really help in the org, and management don't have the imagination to realise that "knowledge" staff might be able to do some grunt work quite happily.