I only use Dancer::Plugin::Database to put my DB configuration where it should be - in your config files. It just cleans up a whole load of potential pitfalls - especially for it's support of multiple named database connections.
I consider it invaluable for that aspect alone.
It also comes with a nice set of "quick" functions (quick_select, quick_insert, etc) These features could be useful for a beginner without intimidating them, but they are powerful enough for an expert to use if they don't want the hassle of setting up DBIx::Class.
This is THE way to have multiple versions of perl installed.
I have 3 versions of perl installed:
1) Latest stable release of perl
2) Version installed on production web servers
3) Older version to test backwards compatibility.
It stops one messing with vendor supplied perl (which could cause issues with system-related tasks) - and allows you to run more modern versions if your vendor insists on providing a horribly out of date version.
The triumvirate of: App::perlbrew, App::cpanminus, and App::cpanoutdated provide a fantastic way of managing your perl environment.
I like how dancer doesn't force you to code in any specific way, it provides the right amount of syntactic sugar to get your app up and running in double quick time - but doesn't get in the way when you want to do something else.
It's nice and light, and can be deployed in many environments. Thumbs up from me!