I have a question about the application of Kyllo v. US to surveillance/searches involving technology.

The majority opinion of Kyllo states the following:
We think that obtaining by sense-enhancing technology any information regarding the interior of the home that could not otherwise have been obtained without physical "intrusion into a constitutionally protected area," Silverman, 365 U. S., at 512, constitutes a search--at least where (as here) the technology in question is not in general public use. This assures preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted. On the basis of this criterion, the information obtained by the thermal imager in this case was the product of a search.
I would think the rule drawn from that statement would be fairly simple: that publicly available technology is acceptable to use for warrantless surveillance, as long as the information it provides could have been obtained without physical intrusion into a home.

However, the footnote to the above states the following:

The dissent's repeated assertion that the thermal imaging did not obtain information regarding the interior of the home, post, at 3, 4 (opinion of Stevens, J.), is simply inaccurate. A thermal imager reveals the relative heat of various rooms in the home. The dissent may not find that information particularly private or important, see post, at 4, 5, 10, but there is no basis for saying it is not information regarding the interior of the home. The dissent's comparison of the thermal imaging to various circumstances in which outside observers might be able to perceive, without technology, the heat of the home--for example, by observing snowmelt on the roof, post, at 3--is quite irrelevant. The fact that equivalent information could sometimes be obtained by other means does not make lawful the use of means that violate the Fourth Amendment.
The footnote seems to say the exact opposite: that the specific technology use must be acceptable, regardless of whether the information could have been obtained without physical intrusion into the home.

Can someone reconcile these two for me?