8 Well, almost never. As of Oracle Database 11g, when features like streams, data guard, log miner, and flashback are used, Oracle disables IMU. Apparently, some serialization issues have caused recovery problems. I suspect this limitation will be resolved over time.

9 It always bothers me when Oracle doesn't use its own features. Are they trying to tell us something?

I'll never forget this: I had just accepted Oracle's offer to join their consulting organization, and an old guy1 at my current workplace asked me very seriously, "Why would you want to work for Oracle? Their database is so slow." While I don't remember my response, I do remember thinking, "I don't really care. I just want out of this place!" But as I came to learn, Oracle was slow, and that was because it successfully manages massive amount of data. My previous employer's database (which was really a glorified virtual storage access method file manager) had no concept of read consistency or rolling a transaction back, so it commonly had corrupted files, which meant that we need to take the database offline and try to rebuild the files. I learned data management capabilities came at a price, both financially and in performance.