They could probably do, but I don't use them on miners directly, I have 400a 3P contactors, each hold 5*80A 3P MCB, I just connect the Sonoff to the contactor so I can control the 5 MCBs with a single smart switch.

Also since the direction of wind is pretty funny where the farm is, also temps changes a lot during the day, I use these smart switches to control the wall fans, so I connect the fan wires directly, but I don't think any set of fans I have go past 10A so the smart switches are not being stressed at all.

While these are cheap, I don't think buying 1 for every individual miner makes economical sense, it would be better to just buy a smart PDU, a smart PDU that can power 24 S19s will be priced at below 1K at most, somewhere near double the price of the basic version, so we can say that all you to pay is 20$ more per miner if you wanted smart vs basic PDU, despite the fact that the smart switch is cheaper than 20$, the smart PDU beats it in terms of safety, installation and a few other things.

Now if you have just 2 miners, then ya 500/2 = $250 more per miner, so I'd stick with the smart switch.