You can say that. But I like to know how much degradation, that could be expected when you increasing ADC clock. The issue have been addressed several times when you search this forum, but I have not seen measurement data, and then it becomes a bit hard to evaluate. This is one of the better threads in the past:
https://forum.arduino.cc/t/fast-sampling-adc/64877
The good thing the data show is, that the ADC works quite well under normal conditions up to an eight time higher conversion frequency with a ADC clock of 1 MHz. I would think that you lost about ½ to 1 bit in accuracy. At 2 MHz, you get at significant decrease, and at some conversion values you lost 3 bit in accuracy. I think this is significant information for a user, that wants shorter ADC conversion time.