Contrary to what some of the commenters said about this being non-useful and just novelty, I think this brings forward one of the best features of Google Maps by cutting out a lot of (potentially frustrating) steps in the UX. Here’s the typical flow for finding street view when searching on maps.google.com:
1. Submit search query
2. Review results list
3. Repeat 1-2 in case user did not find their intended target
4a. Drag the street view marker onto the map OR
4b+5. Click “more” from the results list, then Street view
Instant Google Street View reduces this to just one easy step, and makes it much more fun along the way.
I think the benefit of this is similar to the benefit of Google’s instant search results - making the UX fast, efficient, and fun to discover what you’re looking for. The creator of this should definite consider expanding this to also include street view and satellite view (surprised Google hasn’t done this already).
And I wouldn’t be surprised if he got a call from Google soon for an interview… either for a job offer or a acqui-hire.
You are right, although IMO that benefit comes more from cutting out the in-between steps, rather than the "instant" quality of this application. What I mean is, cutting out all those steps so you just type the address (with autocomplete/suggestions) and immediately see the streetview, is really really great. But--and I realize I might be in a minority here--they didn't need to cut out the final step, which is to press enter to submit :) But then, I've always found that feature in Google Instant very distracting, and go to lengths to disable it for myself.
Either way, that's a very keen observation, there's quite a few steps to go from an address to a streetview in the current form of Google Maps and this app does solve that.