I think the end user base is limited. Would need to be a sports team or a video game maker in my eyes to use that domain.
Pricing for .app is hard to gauge at present with only 10 listed on namebio.
You also have the fact that it is a plural (although the pittsburgh pirates may like it).
Finally the term pirate has negative connotations with the with the "the pirate app" currently being attached to a piracy site.
Solid single word name but as mentioned above, not without issues.
Would price it up at mid $xxxx and consider offers over $1000