It hasn't been "standard on full sites for years", and still isn't now. Only recently with the 'HTTPS everywhere' move has the idea that public sites with no authentication should support HTTPS. And even now, that's not a universally supported opinion, because of its effect on caching.
The BBC has used HTTPS on pages with forms that submit secure data, as has been the historic standard.
Moving a site as massive as the BBC, which spans multiple domains and subdomains and has millions of pages is a big task. Note how you can still see news articles from the late 90s at the same URL. So, yeah, I can understand why writing a blog post about it is worthwhile.