Presumably Mark is still fond of his butter bell 5 years later.
But as a poster noted at the link, the water seal seems to just add problems rather than solve them since we can form airtight seals with other kinds seals that don’t encourage mold. A quick Google didn’t show up any confirmation that butter bells actually preserve butter any better than just an ordinary container. I’m not saying that absence of evidence is proof that they don’t work rather I would love it if someone could provide sound evidence that they do. Without such evidence I don’t find the sales pitch for butter bells to be very convincing given the inconvenience of having to change messy water every few days.