In the 2020 version of the Scrum Guide, the Developers as one of the accountabilities in Scrum is defined as set of people that are committed to creating any aspect of a usable increment each Sprint.
In the same version of the Scrum Guide, it is mentioned that the Scrum Team is accountable for creating a valuable, useful Increment every Sprint.
A number of people have asked me if Usable, Valuable and Useful could be used interchangeably within the context of Scrum and this is my attempt to document my understanding.
A very long time ago, I was coaching a Scrum team where a team member was on an hourly contract and was regularly billing 70-80hrs a week. Among many other ideas that I discussed with client, I advised my client was to transition this consultant away from an hourly contract to a full time with a full-time (40hours a week) contract. With this new arrangement, my client can recruit two full time consultants instead of one person at 70-80hrs week.