pi3 sd card vs Pi4 wifi or ethernet sq

[the_bertrum]

I was wrong, I hadn't considered the noise that is added to the data by switching between 3 sets of switches.

As I said in my response to @WuBai, this is the claim that needs explaining.  No-one has described any way in which noise can alter the information held in the digital description of the information that is transmitted as the signal.
In an analogue system, the signal is the information, noise degrades the signal and therefore the degrades the information.
In a digital system, the information is put into a code that is transmitted as a signal, noise can degrade the signal,

Only correct if the info is not time sensitive. However, music on a CD or a digital file has to be converted to music with a clock signal. In the conversion process, what is known as jitter is often introduced.

Have a read of the following article and you may have a sense of what gets altered in the process:

https://www.stereophile.com/content/cd-j...gic-page-3

Yes, agreed.  "In the conversion process", not in the transport from the storage medium to the convertor, in the case of digital files transmitted over network protocols at least.  Reading a CD is a different case entirely.