I can't think of any use in canon by a Lyran, that doesn't mean it didn't happen. Personally, I don't like the Mech. I want to but it's never worked well for me. It usually does quickly to an ammo explosion... I want to use it, I want it to work well, but sometimes there's just that one Mech that doesn't work well for you.
So, if that's indicative of Lyran use, and when I play it's 99% of the time Lyran, then I don't see them using it much.
One more thing. I'm not really a " wall o steel" player. If I'm playing with mediums I want them to be either faster that this or have better armor... Or both. Interestingly enough, I don't have this problem with the centurion.