The skill of Tsuru makes cannons and make them viable for combat without the need for his interference and will stay even if he is not around. It just makes the cannons more viable as he does not necessarily need to be around just so the cannons remain intact. With this little passive of his that allows him to do those, it only gives more value to it. As for me, I didn't know that some passives of the classes are not present in the Versatile Class. Perhaps it's the main reason why these unique passives are not present in my skill trees is that they are unique to the class that masters their classes rather than to a class that only had the skills that can allow them to be substituted to that class. And I think that is fine, after all, the Versatile Class can also be considered a copycat class that has no originality and is just a class that copies the other classes.