A popular amount of power for USB type device chargers, so economy of scale applies. Economy of scale makes weird pricing happen. Right now on digikey you can

A popular amount of power for USB type device chargers, so economy of scale applies. Economy of scale makes weird pricing happen. Right now on digikey you can buy a "SWI25-12-E-P5" 25 watt PSU for $11.95, or a "KTPS12-12010WA-VI-P1" 12 watt PSU for $12.21. Both are wall mount class 2 supplies, level 2 efficiency standards, even the same connector. The cheaper one has a longer cord, LOL, as yet another weird example of economies of scale. If your application requires 10 watts, a 25 watt supply will quite happily provide 10 watts and run extremely cool for a long time compared to a 12 watt supply being asked to provide 10 watts. I will admit that one mfgr chased safety approvals for euro countries and the other chased safety approvals for USA/Asian countries, but for hobbyist one off purposes, something that passes TUV/CE is approximately as good as something that passed UL, and if you want to sell commercially in the US its usually a paperwork transaction to cross approve something. A bigger problem is X% where X is pretty large, of chinese mgfr equipment has fake safety marks. So for hobbyist purposes you're far safer using a genuine TUV approved supply in the US than graymarket gear with a fake UL mark. So there are minor differences. It would be non-trivial to design something that could pass TUV but fail UL, although someone out there has probably succeeded in the past. The real world market is not magically 100% efficient, so you can absolutely pay 26 cents more for a supply with a shorter cable and lower power output.