In addition to inflections, another factor may be the tendency to use compound words, so that a relevant word in context might not have a space at each end.

In English, Google is pretty good at figuring out when to add spaces in your queries (if you have a typo with your spaces). Similar technology should help it with German?

There's nothing magic about putting a space between words or not. Similar to whether you hyphenate or not.

Maybe it isn't a big deal; my thought was that if you're crawling a website and trying to associate its contents with search terms, parsing an uncommon compound word into the correct parts is going to come up more often in German than in English, especially if you're smaller than Google and German isn't your main focus. Are search engines good enough now to know that a string like electricovenmonitor is about ovens but not covens or Venmo?