I have my catalog hosted on a SSD drive, and I backup it up to another SSD. If I close lightroom and copy past my catalog (almost 8GB) it copies over at a nice 315+ MB/S and is finished within 25 seconds. However, if I choose backup in LR even with optimize and check integrity turned off it takes 5+ minutes. I've never had any issues with my copy paste method, but is LR doing something important with that extra 5 minutes?
Five minutes seems reasonable to me for such a large catalog. Yes, Lightroom is doing important things, like optimizing your catalog, which takes CPU power. I would make regular backups with integrity check turned on.