Hey Tenebrous! Yes, it seems illogical that a much more expensive plane is way worse than the Schuckert, but Sik is right (mostly) in what he says: The Fokker D.VIII is the WW2 starting german airplane. That makes it much faster (like 150 kts with bombs, 230 dropping them WITHOUT ANY SPEED UPGRADES), but, be careful, agility is the same as Nieuport 11's when stock (believe me, the only thing that changes in the spec sheet is speed, not maneuverability).
Then I highly recommend to keep your Siemens and upgrade it before acquiring one of those low tier WW2, as it's much better for turnfight, it has a higher bomb load and much more ammo, and you can use it in both servers (WW1 and WW2).
Then what's the Fokker useful for? Well, the Fokker is a poor purchase for most of uses since it's extremely expensive and not much better than WW1 aircraft, it's even worse in many aspects. However, it's extremely beautiful, no plane is as smooth, sleek or elegant as the Razor:
Another good fact of this plane is that It's simply the best for head-on attack, because it has a parasol monowing (and many also say that the wing is glitched and it's unhittable). This allows the Razor to have much less surface to get bullets than the rest of the in-game aircraft (WW2 included), which allows you to literally destroy every enemy aircraft without getting a single hit. This is something that I've never liked of this plane, it makes games too unbalanced, even with my poor aim (with this plane

) I can easily bring down the whole enemy team without them getting a single shot at me.
So, I recommend you to upgrade your Siemens instead of purchasing this plane. If you want a WW2 airplane, then save a bit more for much better performing aircraft like the A6M Zero, the BF109 or the jets. I hope this helped you!