I wonder if they are profitable, or if some sort of government support is involved. I don't think power for all those lights is particularly cheap in Singapore, and the competition in the surrounding countries has cheap labor and lots of free sun and rain.
Bringing necessities (water, food, energy) local is worth subsidizing. For those who doubt, just look at current events. Two morons with the right levers can upend countless critical processes.
There have been vertical farms in Singapore that went bankrupt previously. I don’t think this model has worked very well in general globally, compared to traditional farms. This particular one is producing insanely expensive produce. For example the lettuce that is mentioned is over $14 a pound. It’s also a hydroponic farm which means only some crops can be grown.