In our career we must have used Meta a hundred times for different designs, both web and print counted. A current check over at Typekit (Adobe Fonts since a couple of weeks) tells us that we have Meta implemented for 18 sites. Most of them have Meta together with something else, but never the less, we use it a lot.
The reason for this is easy to answer. Meta comes in a variety of cuts and that makes it easy to implement it for headlines, body text and breadcrumbs with a consistent style. It has been meticulously kerned for the web, so that the font really works well in a browser. There is also the possibility to use very small font sizes, a good example are breadcrumbs and meta information in uppercase with just some letterspacing.
There is one drawback with Meta, that is the numbers which are text figures. That makes Meta hard to use for sites with a more technical content.