We were reviewing this tool for one of our clients — we work with both medium and large enterprises. Currently, they are using Documentum but they are interested in migrating to SharePoint, so they asked us to compare the two. I am part of an IT company where we do a lot of solutions and service-based IT. We do things for many customers from the IT side.
SharePoint Designer is for the developer or the administrator, it's not for the end product (the business user).
We use SharePoint to improve sequencing and workflow design in general, and it can be used to build a workflow process from end-to-end.
We also use the classic version of SharePoint to do work on the master page, pinning, and other things. We can use SharePoint Designer for that. We also copy our data from our SharePoint site by using SharePoint Designer to cut and paste.