This study examines the cost-effectiveness of Vancouver's supervised injection site. InSite was found to decrease needle sharing which alone saves $14 million and 920 life-years over 10 years. Increased knowledge of safe injection practices and referral to methadone maintenance through InSite saves $18 million and 1175 life years over 10 years. The study also considered the health effect of increased use of safe injection practices, the incremental net savings increased to more than $20 million and the number of life-years gained to 1070.
The choice to keep POJOs pure doesn't come without cost. Rather than spending the effort to develop and maintain complex configuration files it is possible to simply use annotations to mark classes and let spring do the rest of the work. Resolving dependencies can be simple if they follow a convention such as matching by type or by name. This is choosing convention over configuration .  It is also arguable that, when refactoring to another framework, removing framework specific annotations would be a trivial part of the task  and many injection annotations are now standardized.