I have a Larkspur I carry daily too and from work. This shoulder pad is necessary if you plan on putting any type of load on the bag as it's pretty uncomfortable without it. The pad is affordable and I guess they keep it optional to keep cost down a bit, but it'd be a good idea just to include it in the original cost.
Pros: Comfortable, cheap
Cons: Should be included with the Larkspur
This review was written in the old system and had content requirements that are different than reviews written today.