Both Laravel and Selenium use PHPUnit's assertions.
In both Laravel and Selenium you write code to make tests (instead of choosing things to do in GUI; e.g. open: google.com, write in: name->queryInput text:"test search", click: name->searchButton).
Both Laravel and Selenium are able to visit webpages, submit forms and check the results. You can automate tests both in Laravel and Selenium by adding PHPUnit command to cron.
So why should I use Selenium for testing in Laravel?
The only thing I could think of is that Selenium allows you to choose a browser in which the pages will be opened. So if your test passes using only Laravel testing it may fail for some browsers, like, say, Internet Explorer.
In this Laracast the author says at 1:00:
One problem with that [testing in Laravel] is, it doesn't include JavaScript support. So instead, we're faking the request, we're getting the response, we're inspecting it but no browser or JavaScript engine is involved in that process.
But what are the cons of faking the requests? How would Selenium help? An example would be perfect.