Well clearly the summons would have to be situational to a degree. Summoning random characters for the fun of it is a given, although conversely there would also have to be a black list.
To think of an example of potential applications, though, I would probably summon a Lucario and then attempt to find out from it what the emotional states of family members are in order to have a better relationship with them. Not that it's that bad or anything, there's just always room for improvement in that regard, you know?
Naturally private consultation would also be used prior to job interviews when the time comes.
Mundane utility that doesn't have a high risk of backfiring horribly just by using it (let's be honest, the more cliche Pokemon answer of Pikachu being used as a living battery is either going to short your stuff or get you seriously hurt) seems like the best use for actually having a reason beyond "why not?"