Just remember that those packages are built to enable you to get up and running with role-based user permissions pretty quickly, and all hooked into Laravel - for example it builds your migration tables for you, has service providers all ready to role.

So what, you could build that yourself. But lets say you have a users, roles and permissions table - if these have many-to-many relationships you'll need to do things like a custom has-many-through relationship on your user model, which can become quite confusing. If you want to learn and have full control, build it yourself - if you want to do something quickly but not have much of a clue whats going on behind the scenes in your app however have a well tested base, use a package.

As to your second questions - no, memcached works on Windows with Laravel, just isn't as easy as Linux to setup.