What is the point of adding vodka to a liqueur recipe?

Well. It’s most likely the alcohol content in the drink. Without it, you just have a sugary syrup.

Liqueurs are heavy and sweet. They are expensive to produce, but cannot sell enough drinks (too heavy and sweet) to meet their margins.
So, the makers of Liqueurs partnered with Big Vodka to mix their wares, which made the Liqueur drinks seem a little lighter, and which made vodka more palatable to drink, and thus and more lethal. Liqueur wins, Vodka wins. Plus, and thus, his and her inhibitions being suppressed, the Consumer had one or two more instead of saying “No more. Too heavy. Too sweet”
Bigger Liqueur sales.
Bigger Vodka sales.
Not that complicated.

@Seek_Kolinahr doesn’t a sugary syrup ferment over time? Or is that just vinegar?

@josie I laugh, but I don’t understand. The stuff’s not ready to drink yet, so that’s not the problem. No, I just don’t get it. I’m still putting in all the vodka I have, it’s just short about 200ml. I’ll just have to wait to taste it to find out how strong the drink is.

A lot of ice can fix all sorts of mixing problems

We used to use cheap vodka as the base of homemade liqueurs, especially kahlua. We were adding so much sugar and flavoring that it overcame the vodka. It’s there to provide alcohol. @DaphneT, syrup doesn’t just ferment, it would take some sort of starter and would take a really long time. Homemade liqueurs are made one weekend and then bottled the next.

SBD