In this case there was so much in-house software already following the processes that Jira would have just been a royal PITA to use without custom plugins. But if your team is lean enough in such terms, I don't see a need for these things to benefit from Jira.
Interesting, do you think that Jira _requires_ that level of integration to be useful or could a simpler (e.g. less plugin development, synchronization with other systems e.t.c.) also be successful?