Earlier this week we reported that Pokémon Bank received a last minute delay and the release date was changed to TBD. Not only did this delay surprise some people, it seems that Club Nintendo was not informed of the delay and have listed that both Pokémon Bank and Poké Transporter will give 15+ coins each.
This, along with the Wii Fit U trial survey, were most likely designed to gauge interest and improve on the service after launch. Considering all these items are uncharted waters for Nintendo, it makes a lot of sense to offer a few coins to make the services viable/better down the road.