Horlicks ais tastes like malted childhood, that creamy biscuit kind of flavour. People order it thinking it is a wholesome malt drink, like something good for you. The powder is malt and sugar, and at the kopitiam they sweeten it further with condensed milk.
That combo lands it around 230 calories, right up there with Milo ais. It is not evil, you do get a bit of protein from the malt and milk, around 6 grams. But it is a sweet treat drink, not a health tonic. Ask for less condensed milk if you want to enjoy it more often.