Well then you might as well worship Alduin and his dragon priests.
Alduin is not a Deity. Dragon are by nature Immortal, and Alduin was the First Dragon created by Akatosh, but he never Ascended/Mantled Akatosh/achieved CHIM. The only reason Parthurnax couldn't defeat/stop Alduin is because of Alduins power, but Parthurnax reveres/worsips Akatosh, not Alduin. Alduin jealously guards the right to eat the Souls in Sovngarde because it is his right as First Created by Akatosh, and it is within his title as the World Eater, not because he is divine.
The Dragon Priests received power from the Dragons because the Dragons had such a mastery of Magic/Thu'um, not because they are Deific beings.