Fixtures are a thin abstraction layer over sample data in your application which allows for better organizing, often complex, data structures representing different entities. If this sounds like a vague description or does not ring the bell maybe an example will speak to you better.
Automated browser tests, in my case, are often part of continuous integration (CI). Failure = no deploy. This naturally creates some expectations towards acceptance/end to end testing framework. I haven’t found the tool which would meet all requirements although CodeceptJS is close. Nevertheless, no matter whether you use Protractor, Nightwatch.js, WebdriverIO, CodeceptJS or anything else based on Selenium you need to set it up and make it talk to the browser.