It’s highly relevant, notable, and symbolic that after pronouncing justice on the Velaryons who had “slandered” his daughter Rhaenyra’s sons as “Strong bastards”, Viserys stumbled while descending the throne’s towering steps, and though he caught himself, he cut his hand to the bone on a jagged blade. His hand became infected and two fingers had to be amputated, and he was never again truly healthy, nor did he ever sit the throne again.
This is the quote anon refers to, which happens after Viserys orders the protesting and seat-seeking relatives of Vaemond after his death ("A Question of Succession"):
My Answer to the Ask:
I also think that it's highly relevant how the rest of the Velaryons related to Vaemond who tried to claim the Driftmark seat and oust Alyn Velaryon all died (except one) in their attempts ("The Hooded Hand"):
It is interesting how Vaemond tries to take the Driftmark seat for himself by trying to claim Rhaenyra's sons were bastards ("A Question of Succession"):
To use a claim of their illegitimacy to "fight back" against both Viserys' and Corlys' decisions as lords of their houses (that these boys would inherit the specific positions, Jacaerys-the throne, and Lucerys-Driftmark)....and then the Driftmark goes to the legitimized bastard son of Corlys Velaryon, his uncle, anyway! Alyn, who would go on to perform more feats through voyages continuing Corlys' legacy and bringing that sweet-sweet glory and prestige to the house that aristocrats desire almost above all else. Usually. Wasn't Vaemond or any of his sons or nephews--it was the bastard child of his older brother.....funny.
Not only that, like the greens/Alicent, he ended up dead and most of his family dead.
So much for the implication of Viserys' wrong decision concerning the Driftmark claim (not allowing it to go to Vaemond or any of his claiming relatives) and refusing to punish Rhaenyra. And so much for the absolutism of ASoIaF symbolism and Westerosi superstition further disseminated/reaffirmed by already misogynist maesters.
EDIT (9/15/23)
Not only is this chair made out of literal still-sharp-and-pointed-swords (thereby someone/anyone is going to cut themselves regardless of their character), if it supposedly slices unworthy rulers OR slices a ruler when they are making the wrong--either life-saving, strategic, or moral--decision, why are there no reports of Aegon IV getting slashed? Ever?! Or after Aegon V mentally determines to take the eggs to Summerhall or try at all to restore the dragons using unsafe methods?