It's generally not useful to quote flowery language like this, because it's not legally operative. It might justify a particular application of the law, but it isn't the law. It is what lawyers call "dicta."
NSA wiretaps differ in two key ways:
1) At least in theory, they are intended to capture foreign communications. People not on U.S. soil who are not U.S. citizens enjoy no protections under our Constitution.
2) This case is based on interpreting the "search incident to arrest" exception to the 4th amendment's warrant requirement. The essence of the exception is that while a warrantless search of someone's person is potentially the most egregious of fourth amendment violations ("person" being specifically enumerated in the text of the 4th amendment), it is nonetheless reasonable in the context of a search incident to arrest,[1] where it might be necessary in order to secure the arrestee, who might have a gun or throw away evidence.
An undersea cable is totally different. It is not a search of anybody's "person" but a search of something containing signals that people are transmitting out into the world. There are four specific things enumerated in the 4th amendment: someone's house, person, papers, and effects. It is clear how searching a phone in someone's pocket is a search both of their person and their effects. But signals transmitted out into the world does not fit neatly into any of those four categories. For example if those signals were transmitted via radio versus fiber optic cable, would it be a "search" to listen in on them?
Now, the language of the case is relevant in that it suggests the Court may be open to a more expansive reading of the 4th amendment when it comes to digital data. There is no way the conservatives on the court would favor extraterritorial application of the Constitution with regards to undersea wiretaps, but it could bode well for challenges to domestic surveillance.
[1] Incidentally, as the opinion notes, the touchstone of the 4th amendment is "reasonableness." This fuzzy word is used explicitly in the Constitution to allow judges to engage in line drawing and balancing the interests of law enforcement with privacy rights.