Is there any disadvantage using Web View over Native View?
As Spencer mentioned, there are a bunch of customizations that are not available in the WebView; the display via the web is really only in there now to support those who may have customized the web templates to display things that won't ever display in Native view (such as custom HTML).
You are correct, it works fine in Web View.
The web browsers are likely rendering the images at a much lower level than normal applications use, and are probably better handling updates that happen before a redraw (or else just drawing so fast it doesn't matter). Again, this is a guess.
Are the images you set at 10s showing and refreshing okay?