When I had my cable upgraded to digital, there were problems with pixelation on many channels as well as errors when trying to tune SDV channels. I had the coax running through the coax surge protector section of a Rotel RLC-1040 power conditioner.
Removing it from the line allowed everything to work properly. The install technicians said they run into that frequently.
There have also been reported problems of Internet slowness and dropouts associated with coaxial cable surge protectors.
If you were to install one, it would be one like the second link you provided and should be installed outside at the cable drop before any amplifiers or splitters. My cable drop was verified to be properly grounded, so I did not pursue other cable surge protection. Several years later, so far so good (knock on MDF).
Steve