That's perfectly fine, using a 600W bequiet PSU here. (A PSU's efficiency sweet spot is around 50-60%, so consider that for your choice)
Alrighty! I was wanting to get a new PSU for my workstation anyway due to new GPU, so might just take out the modular 550W PSU from it and run the Apollo on it. Then I'll also have headroom for some stick miners or another Apollo etc. in the future.
The cool thing of the Apollo 200W PSU is that it's so compact and passive, but I guess it will still be possible to tuck the whole setup away nicely even with a full size ATX PSU.