All the cases outside of "oh, I dump my thoughts on the page once a year".
Even for a blog in the modern world I would like:
- automatic crossposting to Twitter and Facebook
- automatic retrieval and reformatting of external content (because, for example, twitter embeds are very cumbersome, heavy and slow)
- automatic retrieval of video and images from external sites (youtube, instagram, twitter etc.) because of link rot
- delayed publishing
- search
- and a plethora of other things
Yes, you can stitch togethe a bunch of "serverless" stuff for this, but you've just "replaced" the "traditional server backend" with a bunch of traditional server backends.
This IMO should have been the main point of the article, not VPSes. No one can argue that a maintaining a live website is better if a few HTML pages will do.
In your linked article you say:
"Anyway, site search is only a nice-to-have...and folks can just use Google with the site: operator instead"
To me that sounds like a compromise.
I'm out of my depth talking about SSG-powered sites because I've never developed them. My area is frontend design-dev, without the engineering stripes or desire for overly complicated builds. That's why PHP and the traditional dynamic sites work for me.
PHP, javascript, templates and a good reliable CMS allows me - the non-engineer, to do really interesting things such as site search with lots of added unique tricks to make users happy when they search for things.
Beyond my needs, the non-technical people I build sites for need to manage the content easily. That's where I scratch my head with the SSG offerings in that regard. Where the CMS is often the lowest priority, with bizarre suggestions and workarounds to fill the CMS void. For complex content-heavy sites with lots of products, forms, landing pages and categories, a good CMS is really important... and a general architecture that isn't scattered around big tech services IMHO.
Re: search. It's not that site search is impossible, or even particularly hard, with a JAMstack site. It's just that I didn't consider it MVP for my personal site. I know how it can be done, and I'll implement it when I have time.
Re: CMS. I know where you're coming from, I spent a good decade or so specialising in traditional CMSes / frameworks myself, mainly Drupal and Django. There are various answers to the CMS question for static sites - the ones that I'm most familiar with are https://forestry.io/ and https://tina.io/ (and I've heard no end of buzz about <https://www.sanity.io/>). Those solutions are solid, I wouldn't call them "bizarre suggestions and workarounds". And they're good enough for most needs, IMHO. But I haven't tried pitching them to clients yet.