The Wikipedia article for it shows only skepticism regarding it, with no professional sources arguing for its existence.

https://en.wikipedia.org/wiki/Qi#Scientific_view

Could you show the evidence to the contrary?

Also, potentially beneficial effects of acupuncture do not imply anything about the existence of qi.

Depends on what you mean by existence? Detectable by modern instrumentation? What if Qi is an extremely useful system of mental organization, allowing practitioners to fine-tune their own body's operation. There is plenty of evidence that this is possible (see mindfullness / trancendental meditation) which have concrete isomorphisms (so to speak) to the concept of Qi.