When internal developer tools are good, and they’re used consistently, they improve the productivity and efficiency of all downstream developers. The real benefit is a “rising tide lifts all boats” effect – all developers on your team become tangibly better from using a well-designed tool, and those that weren’t efficient at a particular set of tasks become demonstrably more efficient using the tool. This was an unexpectedly pleasant part of my experience building internal tools: I got to work with teams from all around my company, which can make you more aware of what other parts of your company are working on.