Profile Relationship
The profile relationship isn't added by default, but is suggested whenever you have several pieces of equipment that share a numeric or alphabetical sequence.
For example, if you have several machines doing the same basic job that are numbered 1-6 or A-F, creating a profile relationship and linking them up in order makes it easy to see that there are several assets performing the same job.
It's also extremely valuable for charting - you can use the relationship as the x-axis on a chart to allow you to very quickly display the load balance across similar assets.