Ok, I just had to post this and play the Devils Advocate since I have been thinking off and on about it today. I am seeing all these blog posts where developers are thinking that GE in a web page is the best thing since sliced bread and that everyone is switching over to use it in their websites.
But, what about the average Joe user though? How are they adapting to this sudden change and in some cases, lack of access because they do not use Windows? Now they are coming to a site that is broken for them. Are end users rushing out to download this plug-in so they can have the latest and greatest? Or are they walking away?
Other questions coming to mind.. how are you're average Joe and Jane users managing the interface and navigation after they do decide to install the plug-in?
Just because it is from Google and it is a variant of Google Earth does NOT automatically mean everyone is going to be rushing to be first in line.
Edit: Here, Hear.. you get the point, don't ya?
Edit 2: Well, if you read the slashdot comments, the average user is going "Meh!" about the Google Earth plug-in version.

I have yet to install the plugin so I can't comment on anything other than I'm lazy.
Same here.. but I am not a plug-in installing kind of person.
So is the Firefox/ IE battle.... sometimes even I forget to check a site (in the short term) between the two browsers and realize I\'m totally messing up my IE visitors.
I had a look on a friends Windows’ laptop just because…
It’s neat, but because it’s a plug–in you have to install, restart browser etc, it loses an awful lot of appeal to me. If they bundle the plug–in with the next google earth update, then that would be sweet!
I can’t see anyone I know choosing the plug–in over maps.google.*, just because it’s soo much easier and quicker to get to where you’re needing with that.
If they added it to the current gmaps as a new option, without requiring developer changes [giving the user the option to view in 3D], I think it would be a good thing.
As for the usual single–platform, closed–source approach, I hate it. It’s bad being 3rd on the list of supported platforms always