Got the bundle now

First I installed both games en they are working without the steam keys....
So like explained on the site from Humble I installed the app Steam on my computer... and I registered the both keys!
I din't installed from Steam their library stuff for both games on my computer... because the games are working and my suspicion feelings for strange programs.
And Little Snitch was showing me a lot connections from the Steam app.
So why do I need Steam and what does it for the game and why does it need all these connections???
Kind regards,
EB