Uses of single-partition disk configuration

Solution 1:

Is there any reason why a partition would be used in this case rather than a whole disk?

Few reasons I can think of:

• People (read: future admins) expect partition tables. Having them saves WTF moments. Filesystem on entire device may seem simpler – "I'm saving one abstraction layer, yay!" – but it's not one abstraction layer less, it's one possibility more.
• Programs may expect a partition table first, a filesystem later. See what can happen when things go wrong.

In my opinion the first reason alone is good enough. Additionally (these may not apply to your case though):

• In case you need to shrink the filesystem and create a multi-partition setup, it's easier when you already have a partition table.
• In case you need to place a bootloader somewhere, MBR with a single partition at some standard offset is a way better starting point than a filesystem on the entire device. I guess with GPT the problem converges to the point above.

However if you need to move the disk back and forth between an enclosure that mangles its logical sector size and any setup that doesn't, a filesystem on the entire device would allow you to mount easier. Compare this question and my answer there.