Launching from the Equator, Eastward, is the most energy efficient way to get to orbit, but not everybody is after equatorial orbits or geostationary orbits.
Lot of sats are for example spying sats, and these can use polar orbits (as the earth rotates under the sat, sat will at some point map the whole earth), or more fancy orbits that you can read about in this guide here:
http://www.braeunig.us/space/orbmech.htm#types
While we're getting used to rockets "just working", it's still rocket science. Things go wrong and you'd rather have the hundred tons of fuel and aluminium (or steel since Starship) going supersonic into the ocean. Unless you're Chinese or Russian, they don't mind.
FTA: “It will allow up to 30 satellites and other payloads to be launched into commercially valuable polar, sun-synchronous orbits, which are in high demand from satellite operators for communications and Earth observation“
⇒ they’re aiming for the part of the market where that doesn’t matter.
The Norwegians have had a sounding rocket launch site at Andoya at 69N for decades- perfect for studying the sun- and are talking about trying to turn it into a sun-sync earth observing micro-satellite launch point.
I honestly don't know why the Germans are trying to turn an old Chain Home radar station in the Shetlands into an orbital rocket launch site. For sun-sync polar orbits, it doesn't really matter what latitude you launch from, you aren't getting any benefit anyway, but I wonder at exactly how many of these sun-sync earth observing satellites are going to be launched by the ESA or Europeans in general. This doesn't seem like a particularly large market to me.
> I honestly don't know why the Germans are trying to turn an old Chain Home radar station in the Shetlands into an orbital rocket launch site.
Well, they aren't. RFA is just one of many customers, which also include British and US companies. SaxaVord spaceport is operated by a Scottish company and there's no connection to anything German other than some customers being German companies. Lockheed Martin UK and Californian ABL Space Systems are operating from there as well.
Earth observation is still growing. And it seems to be an area where countries want to have the own capability for national security and prestige reasons.
What country other than the UK is going to want their national security and prestige earth observing satellites to be launched from the UK? Especially one that is okay with doing it from the UK but not the US, which has rather more experience with launching from VAFB.
