Well obviously as FISA-702 does not require a judge. If they had gone down the 702 route then the FBI/DoJ could have circumvented greater legal scrutiny and I am sure there would have been justified uproar. Indeed your Treehouse hugging friends have been diving down the (wrong) 702 rabbit-hole for a while making accusations that the FBI were using this route supported by contractors such as Fusion GPS (remember that redacted document you posted with great huff and puff) to get around legitimate scrutiny.
The fact that the "traditional" FISA route was used which requires greater independent scrutiny supports the proposition that due process was followed rather than undermines it.
Given that the warrant was served on 21 October and Page left the Trump campaign over a month before then there would be no risk of Trump or his officials being caught in any surveillance unless they continued contact after he left would there?