About a year and a half ago I bought a home, after looking at dozens of houses. I found my home on Zillow, and I agree with your general sentiment about its strengths and weaknesses. In my case, my home had been on the market over a year so it had been on Zillow a long time, but I found a lot of homes that I wanted to look at on Zillow that were already sold or under contract and Zillow had not been updated for days.

I tried several agents before settling on one, and she was awesome helping my wife and I to tour dozens of homes during our search. Handling the actual negotiation/transaction was cake compared to the time and effort she put in taking us on house tours!

Of course, if the security problems could be solved, I would probably not have needed an agent for that :)