TumbleBit would be interesting if incorporated to Bitcoin, as an altcoin it will certainly be a scam like all spin-offs from proposed privacy-enhancing Bitcoin extensions: Dash/Darkcoin(Coinjoin), Zcash(Zerocoin/cash) etc, this is getting old.
A Cryptocurrency needs much more than privacy/fungibility, it needs scalability (Monero got it), a decent launch (Monero was fair), different mining algo (Monero has Cryptonight), substantial enhancements (Cryptonote is not a Bitcoin fork but created from scratch as a bold and successful re-interpretation of Satoshi Nakamoto original dream). Even the original Cryptonote (Bytecoin) is a scam, the only thing that saved it (Monero) as a clean fork was the merits of the protocol that I stated before and the yuge upgrades all over the code.

edit:


scam.