When you think about website monitoring usually you recall uptime monitoring (if the website is up and running) or infrastructure servers monitoring (to see how busy servers are).
But there are some other things you would love to monitor when you have website. For example it would be great to actually check if pages are working and there are no errors on them. Or you would like to keep checking and be notified immediately if your website was hacked.
This is where automated visual monitoring could play a good role.
Hacked or defaced website
Problems with redirects
If you are working on the website and moving content around (changing its URLs) you would love to be sure that whatever happens content is accessible using old URLs. This is another use case where usual monitoring tools like checking response status won't work that well. In case of visual testing we can ensure that visually page stays the same after all the redirects. In our practice we even had situations with inifinite redirects that are very nasty problems. These types of problems are very easy to track if you set all your website monitored regularly with automated visual testing.
Problems with server, error messages on code level
Another big part of potential problems is of course if server starts to fail and produces 5xx or 4xx errors instead of serving pages. Or even worse after update of your server software (version of php, php libraries, mysql etc.) you start getting errors displayed on web pages. In this case automated visual testing also would be able to give you report where changes happened and let your development team react fast to fix bugs.
Please share your thoughts in comments what kind of other monitoring you use on your projects? Maybe you use visual monitoring to catch some other cases?