AFAIK the typical transformer design includes the primary being wrapped closer to the core and the secondary being wrapped atop of primary and so further from the core. Why this way and not the other way around?
This question presumably mentions the design where the secondary is closer to the core and made of thick wide aluminum tape. It's a last mile distribution grid transformer with primary being fed with something like 6 kilovolts and secondary producing something like 110-230 volts (consumer voltage), so the secondary has 30-60 times higher current than the primary and with that current I think it's reasonable to place the secondary closer to the center so that each turn is shorter and the secondary itself is shorter and therefore has lower resistance and lower losses.
The same reasoning should apply to all transformers which lower the voltage - the secondary voltage is usually 10-20 times lower than the primary voltage (110-230 volts primary vs 12 volts secondary is typical) - it's reasonable to keep the secondary wire as short as possible to lower the losses (and save some thick wire).
Yet I've never seen a transformer with a secondary located closer to the core (except in the linked to question).
Why is primary winding usually closer to the transformer center and has smaller coil loops?