If Australia refined _all_ of the 40,000kt of Bauxite we export each year into "frozen electricity" Aluminium, that'd only require about 600GWh, or about 4% of the 1.7GW 24x7, or 15,000GWh per year this would send to Singapore.
Large datacenter are in the 100MW sort of range, so only single digit GWh per year.
Australia generates a few hundred TWh per year. 272 TWh in 2021/22 - or 272,000GWh, around 20 times what this project will export to Singapore.
Data centers and Aluminium and Iron smelters are big electricity consumers. But they barely even move the needle compared to cities with millions of households.
Approximating bauxite as pure aluminum oxide [1], 40 million tons of bauxite contains about 21 million tons of aluminum. A ton of aluminum takes about 14 megawatt hours of electricity to produce [2]. That would be about 294,000,000 megawatt hours (294,000 gigawatt hours, or 294 terawatt hours) to turn Australia's bauxite exports into aluminum. Australia could easily double its electricity production/consumption to refine bauxite into aluminum metal instead of exporting the bauxite.
You're off 3 orders of magnitude, 40,000,000,000 kg x 15,000 Wh/kg = 600TWh (you likely tripped on the kt, which is 1000x1000kg, at least I did the first time I ran your numbers). That's not 0.2% of Australia's energy use but 200%.
Ha! It figures. Further down that thread I wrote: "Also, I'm notorious for dropping three orders of magnitude when doing mental math using kilo/mega/giga/tera prefixes."
Turns out when you do the math right, Aluminium _is_ frozen electricity.
Natural resource sales send USD to Australia. AUD is now worth more because it is backed by more USD. Manufactured exports are also traded in USD, so Australian exports become much more expensive because workers and local materials are paid for in AUD.
For that, you'd need to make massive investments in a part of that world that has mostly untouched nature.
It might or might not be a good idea. But you need to then compare those massive investments to the relatively modest investment of the power cable to bring the electricity to a part of that world that already has all the other infrastructure needed, and also already has lots of water.