The main reason that people use Internet Explorer in Crossover is to access "IE-only" secure websites/webapps. These websites can be configured to call on a wide variety of windows components (particularly if they use ActiveX controls), and in some cases the components needed by a given function or tool on a website may not be implemented in Crossover. Because of this, there are quite a few "IE-only" websites that don't work properly, or at all, in IE-via-Crossover.
As a general rule, these website will either "just work" via IE7 in Crossover, or they won't. There is very little additional configuration that can be done to IE7 once it's properly installed in Crossover (apart from those tweaks mentioned in the other "Tips & Tricks" articles on this page). If Internet Explorer 7 and its associated packages installed successfully in Crossover, and you're able to access and login to your "IE-only" website, it's very important to test the site thoroughly and make note of any bugs or failures that you observe, and determine if these failures render the website unusable for your needs. In almost every case these bugs or failures will not be readily solvable.