A recent article entitled “Breaking MimbleWimble’s privacy model” published by Ivan Bogatyy has been causing a stir as the author claims of a “new attack” that ‘traces 96% of all (MimbleWimble) sender and recipient addresses in real time’. The attack costs $60/week of AWS (Amazon Web Services) something that leads Bogatyy to conculde that: https://litecoin.com/en/news/the-litecoin-mimblewimble-proposal-is-about-fungibility-not-privacy
Sorry, fungibility means you can't track say USD bills without knowing the serial number and amount on each bill....by hand this is a .. big pain in the ass...
as far as I can tell the mimblewimble problem you could use computer/math/processing TO track the supposed mimblewimble coins thus eliminating fungibility...
something you could not do with the fungibility of cash...scanning each serial number. Indeed, the problem with mimblewimble is you could track crypto in the same manner as bitcoin.
Thus I don't get the Fungibility argrument..you need privacy for fungaiblity to work..or at least like the case of cash...very difficult to just pull individual serial numbers or
whatever out of the sky to track the currency if it is plain cash. If mimblewimble is broken, IMHO, it is no different than Bitcoin and other Altcoins for having NO real Fungibility.
Thus neither BTC or any mimblewimble coin has any fungibility. Thus right back where we started with the fungibility problem with Bitcoin and other Altcoins.