How the heck is the strut mount damaged? The rubber isolator sure, but the mount should be fine.
The rubber isolator for the strut is integral in the strut mount. Even if the rubber looks fine, i.e. no cracking, chunking or tearing, the rubber can soften and become more pliable with all the stress and force its exposed to over 100k miles. Its generally a prudent step to just replace the strut mount with the strut (or a shock that is put together much like a strut in the case of the Commander).
If the strut mount ever did go bad, it requires redoing the entire job of replacing the strut to get the old strut mount out and a new one in. So to avoid the chance of having to do the job twice, its prudent to replace the other part that could be close to wearing out while you're doing the job.
The other, like I said, the rubber bushing in the strut does wear (even if it looks ok), it arguably does make a difference in performance to replace the strut mount with the strut.
I just did my shock/struts on my Commander, and replaced the strut mounts with it. I noticed I've gained some ride height in the front, and likely my front had sagged some. I don't know for sure, I would have to see a cross-section diagram of the strut mount, but it could be the fresh strut mount that got me the ride height back. Wish I had measured before and after, so I could tell and report for sure, instead of just guessing, well, it looks higher than before. It could be the bilstein shock itself (maybe a slightly higher spring perch or lower clevis mount) or just the new rubber isolators as well.