I like that there's a visual interface and that templates can be shared by multiple team members. There are lots of work flow and diagramming programs/apps out there. Each has strengths.. Box's strength is that many different aspects of work can be managed and share using a single platform.
Personally, I fund most workflow apps not as useful as simply doing the work, but are an easy, non-threatening way for more senior team members/leaders to share "how-to's" with less experienced staff or team members.
How important is it that you standardize work/task methodology? If it's important and /or if you have quality assurance concerns, Box Relay may be a good option for your organization. Also, if you have lots of files to share, work in a range of locations, need to share info across teams and places.. All of this contributes to making Box Relay a better choice than other less integrated apps.
Relay is useful for codifying work methodologies. Team members can use the resulting templates as guides. They can also propose changes, make suggestions, and question how work is handled. Additionally, the resulting templates provide useful checks to be sure work is done to the quality level required without missing any component.