Is Tumblebit really as big as it seems to be? It can make Bitcoin transactions anonymous (there is clearly a huge market for this looking at the valuation of coins like zcash/monero/dash). For zcash, shielded addresses is not in effect yet but it is something they are working on, for monero this is default (all addresses are shielded and thus by knowing an address you cannot know how many coins are associated with that address).

Does tumblebit do anything other than hide the transaction amount? Ie if you know the sender address and the receiver address, you can still see how many coins are associated with the address and could (in theory) infer how many coins were transacted? If this is so, how will it compete with say Monero (or zcash in the future if they solve some critical problems) which is already capable of completely anonymous transactions with shielded addresses? How heavy on resources with it be (ie would it be able to deal with the volume monero currently has)? I guess this would depend on how many masternodes are up.