using pure beeswax as a rust preventative on tools works for storage or shipping might be ok. Thin coatings could only be done on a warm part.
Mixing beeswax with other things to thin it down could be done. For instance, a mixture of 50-50 alox and beeswax was popular as a bullet lubricant for many years on cast bullets. Alox is no longer made, but other lubes are available that are similar. Before alox, various oils were used for the same purpose.
As far as coating tools goes, It would work fine unless you want to use the tool. Then the coating would just wear off immediately.
From at least WWI to Vietnam era, cosmoline was the preferred rust preventative of steel parts. In war, often substitutes were used. I have run into a few things small items that definitely were not in cosmoline and may have been in a beeswax mixture (sight parts for a P-17 Enfield and a winter trigger for an M-1 Garand come to mind) I can see where beeswax would actually be better in these cases to save time using them.
One rifle of note that is an oddball .. a Remmington rolling block in .43 Egyptian (French Foreign Legion rifle from the 1800s). I'm pretty sure it was packed in beeswax and camel dung ... not positive about the beeswax. The camel dung is pretty obvious when you start cleaning it.