Why does making flavoured beer substantially lower its value to the point where its pointless?

Rice lager (grand reserve) + fruit juice (watermelon) says the sell value will be 7s 59c yet when crafted its worth 3s 58c which is less than just selling both individually by a massive margin.

So why bother? What's the point? Infact you could use this with pretty much all the default cocktails tbh minus egg nog.