[phektus]

Even in a team of specialists, some of the work they do can be off-loaded to a full-stack developer to free them up for tasks that require more of their expertise.

For example, a front-end specialist would be better off optimising the slow page response times of the product's news feed or implementing a new application page altogether than, say, adjusting css that break on a few view ports. In a big team, you can push the CSS fixing job to a junior; but in a lean team, it's better if this goes to a generalist in your team.

If your backend dev is busy on implementing OAuth, he can off-load fixing a bug that has a small fix but is hard to test like a minor refactor. You compound this "minor" jobs and you will need a lot of junior staff to help on the load, or you could hire a full-stack developer to help with the whole team.

Eventually this generalist gains a good understanding of the full stack, as his title implies, and can contribute good ideas that affect all parts of the system. They also make good tech leads because they can interact and empathise with all members, and can call out decisions that may seem good on one part of the stack but could have horrible implications on the other end. Some progress to Architects simply because they have the bird's eye-view of the whole system.

Lastly, if you are a fledgling web startup, it would work against your business interests to hire an expensive specialist right away.

[taurath]

The difference in flexibility between having 4 backend and 3 frontend engineers on a team and having 2 backend 3 flex and 2 frontend engineers is a huge gain in what that team can commit to in any given period.