I have actually cut open some similarly suspicious (because of size) relays that were being used as contractors in load/demand management devices installed by our local electric company. these are used to turn off high load items in a household, in response to radio (or cellular) commands from the power company during peak load. Some of these control air conditioners, via series circuit with the homeowner thermostat. But another one was actually controlling my 1HP pool pump too! I took apart that relay's outer case and it was a little heftier than the contact in that SONGLE relay, but still nothing like one might expect. And those were all NC contacts mind you, so they were always energized. I did some research on that part and found it could be had for about $35 USD. Quite expensive compared to the China (SONGLE) part, more than 10X more in fact. But cost alone can't be a gauge of actual ratings.
Currently I'm using an OMRON LY4-12VDC relay, with each of its 10 amp contacts ganged together. Those relays can be had for $12, and I don't mind the cost but its not as convenient as a single contact. I will do some testing with the SONGLE, but I think you've all convinced me not to get my hopes high.
And like I said, if it does even half way decent, I might try making a PCB that puts two of them together.