I'm pretty sure Sedeprivationism and Sede-impoundism, as well as Sede-impeditism, were a "thing" before Fr. Chazal. He made up neither of these positions. I had heard of all of these 23+ years ago.
Of course, Sean Johnson liked to lump them all into "Sede-whatever" or "Sedevacantist", all of whom he would ban and not speak to. But when something has a different meaning, it needs a different name. A different "word" for a different concept, a different reality. Each distinct concept needs a concise way to refer to it.
Sure. I personally think that sedeprivationism and the position that Fr. Chazal articulated are the same, for all practical intents and purposes, but Fr. insists that there's a difference, so out of deference to him, I throw in the extra term. At one point, he was asked what he would call it, and he rattled off some 7-syllable phrase that included being impounded by virtue of some canon, etc. ... that I then shortened to sedeimpoundism. I think the term "impounded" does accurately convey the essence of his position, where the Pope is there, holding office, but in a state of suspension where he can't licitly exercise the office.
At the end of the day, as I said, I'm actually not too interested in debating the finer points of the differences in these opinions, nor in debating the "5 Opinions". Much better minds than ours have failed to agree on these questions, and we're not going to resolve the debate here.
I focus entirely on the nature and indefectibility of the Church and the papacy.
1) To me, it's clear to anyone who has a modicuм of
sensus Catholicus left ... something which Salza has defeated with great violence to himself, resulting in split brain and a kind of schizophrenia ... that there's a radical incompatibility between the Conciliar Church and the Catholic Church. That's why we're Trad Catholics. If this were just a set of accidental differences, then we would be guilty of schism for breaking away from the Church.
2) Nature of the Papacy, the obligation of Catholics to be in communion with and in submission to the Papal Magisterium, the protection of the Holy Ghost over the papacy that would prevent the Pope from effecting #1 above, a radical and destructive transformation of the Catholic Church.
As far as I'm concerned, if someone upholds these two, I have no quarrel with them, and I'm not interested in debating it. Archbishop Lefebvre, for instance, upheld both these.
Now if you want to argue privationist this or poundist that or vaccantist this, or, as +Lefebvre did, say "I don't know", or, heck, if you wanted to claim that the reason for the crisis is because Montini was drugged, held captive in the Vatican dungeons, and replaced by some big-eared crooked-nosed double ... more power to you. I don't actually care. I just care about #1 and #2 above.