Is car battery emergency power bank useful?

Under normal conditions, the car can indeed be started many times, eliminating the trouble of wiring. What I mean by normal conditions is that the car is in an ideal environment, such as when the ambient temperature is suitable and the car is normal and has no problems. But one thing to note is that the claim that it can start the car xx times is just a joke. Because the resistance to starting the engine is small and the time is short when the car is hot, the hot car can be started n times continuously. I have seen many cases of failure to start, all in winter. If the car fails to start when the temperature is minus 20 to 30 degrees in winter, and you take out the power bank to start it, it will be basically the same as not plugging it in. It just makes the engine rotate at low speed for a few times. Why? It is because the engine resistance is too large at low temperatures, and the starter requires more current to start the engine. Therefore, after several ignition failures in winter, the battery often runs out of power!