SSDs are good for boxes that are latency-bound or subject to vibration. For a box that sits under a TV set and spends most of its active life throwing 1Gb mpeg4 files down an HDMI cable, not so much.
- Less noise
- Less heat
- Smaller
- Faster boot time
- More bandwidth
- Less noise true, but peg a Mac Mini or MacBook Pro's hard drive to max and see if you can hear it from, oh, 5 feet away.
- This isn't a mobile device, so heat with regards to user comfort is not an issue. Until it presents a reliability problem, heat is a non-factor for a desktop.
- Smaller, and much more expensive per GB. Much more. Shaving another quarter inch off the enclosure also seems like a paltry gain for a much more expensive storage device.
- For a machine that reboots very rarely, this is moot. This is clearly meant as an always-on device (hence the low power usage to begin with) sucking down torrents all day or some such.
- It's a media-centric device. It will download stuff, listen to music, stream video... what kind of bandwidth does it need?
SSDs in a Mac Mini would be a Ferrari in a school zone - cool, and done purely for the sake of style, but let's not pretend that there are significant practical reasons for doing this.