Comment by skynet-9000

Are you talking about a laptop power supply vs an ATX desktop power supply? Even most enthusiast ATX power supplies that I've seen don't use SMT for the main power board, probably because of the weight of the components.

For example, Here's a (very packed!) modern 1600 watt (!) powersupply from Corsair: https://cdn.cplonline.com.au/media/description/POW-COR-AX160...

You can definitely see that SMT is used for the distribution side, but you can see single-layer boards used closer to the A/C side as well.