Meh, not defending Apple in any way but RPM isn't a very useful metric without other specs on the drive.
Battery life and durability are better on 5400 drives. Performance is a tricky one too. Depending on use case, say a PC doing lots of large sequential data (Media)? 10/15k with high IOP and random access times don't actually help much when streaming home movies instead of serving up highly concurrent database records.
This is Apple doing Apple; very well-designed but midrange hardware with a premium price tag.
Have you used the 5,400 RPM iMac? It's incredibly laggy out of the box. Even booting takes 1-3 full minutes. It crunches just opening apps. With all that other hardware, it's just a waste: you're drinking an i7 through a straw.
Have you used a MacBook Pro (2012 or older) or iMac with a regular hard drive? You can't even surf the web with them and they take 2 minutes to boot up.
Battery life and durability are better on 5400 drives. Performance is a tricky one too. Depending on use case, say a PC doing lots of large sequential data (Media)? 10/15k with high IOP and random access times don't actually help much when streaming home movies instead of serving up highly concurrent database records.
This is Apple doing Apple; very well-designed but midrange hardware with a premium price tag.