Well. I think comparing Mapillary photos to Panoramio or single photos uploaded to Google Maps is like comparing people who currently drive passenger cars and what they see to those that have lined up for private space flights. That is, many are doing the prior and seeing a lot and benefiting from it monetarily. As for the latter, there are only a few people doing it today and they have seen very "little", and will not see that much (in quantity) in the near future.
Ok, my comparison is half-baked too, but the point is that these are two different things. It's a bit like OSM was only a few years ago -- not right to compare it to Google Maps. Or comparing Wikipedia to Encyclopedia Britannica in 2003. Or Linux to Windoze in 1996.
The whole premise of Mapillary, or OSM, or Wikipedia, Linux, etc, are totally different. (i) Just for the fun of it -- ok, this is not really true for Mapillary as it's a private venture, (ii) open data, open source make it totally different for actually most users in terms of freedom, possibilities and legal strings attached -- and money (iii) community-based / peer prodcution -- make it different socially, which is true "even" for Mapillary (as a private venture).
I've taken over 300k photos all around Nicaragua covering almost half of the country's primary and secondary highway network, nearly 300km of the 400km of bus routes of Managua the capital, many neat off road / off the beaten path places, and many beautiful passages. I also know that the photos have been used to map things both locally and remotely. I've used the photos I've taken as an example to lobby the use of Mapillary to a number of development organizations because I know that it would help make international / national development significantly more efficient and effective. And I've gotten some good response even though my direct actions haven't lead to action that much (even though it has turned some important heads). Elsewhere on the globe there are tangible examples of Mapillary use, e.g. with Mapillary use by the World Bank and the Red Cross. These things can and I think will be huge.
Going back to who are viewing the photos now and comparisons, namely Google's services, we need to remember that there are literally hundreds of millions of users (actually the order of magnitude is billion). They've become the verb that people across the globe use for checking things out both searching the web as well as the map. Getting even hundreds of millions of hits to some beautiful photos that are featured in Google Maps and Google earth is not that surprising, even though it is amazing of course. Mapillary hasn't really built any features to bookmark or rate or make list(s) of nice photos (like especially Flickr but also Google has done). Not yet, that is. With (initially and/or comparatively) small / little resourced ventures like Mapillary, OSM, Wikipedia or Linux, etc one needs to take a helicopter view to things.
Or then just do things for the fun of it!
PS. Forgot to mention another major issue in comparing single views of a Mapillary photo to a Google service photo -- or Flickr or alike for that matter: single photos are vetted. Mapillary views should be compared to a single screen view in Google Street View. I bet by far most of those go just as unviewed as Mapillary photos...