It’s all the time doable to precise spending circumstances of their disjunctive regular kind, that’s as a top-level “OR” of every particular person spending paths. Taproot permits for every spending path to be in its personal leaf. It’s right to assert that doing so can be maximally personal as it will reveal the strict minimal of details about the spending circumstances that have been obtainable for this output.
However there may be a number of dimensions to optimize for when compiling a spending coverage to a Script. Apart from privateness, there may be effectivity. It’s not right to assert that it is all the time extra environment friendly to make use of one Taproot leaf per spending path, or to change to P2WSH, than to make use of an OP_IF in a Taproot leaf. For example, take a easy coverage like “2 keys can all the time spend collectively, 2 different keys can all the time spend after both every week or previous block 1’000’000”. A Taproot with two leaves can be extra environment friendly on this case than one with three, or than utilizing P2WSH. In fact the extra spending paths you’ve gotten, the larger the features in comparison with utilizing P2WSH.
Moreover this evaluation ignores a 3rd optimization dimension: the likelihood of every spending path. Good contracts typically have some paths which can be used ceaselessly and others which can be hardly ever used. Taproot lets customers place seemingly paths greater within the Merkle tree, making frequent spends cheaper whereas pushing additional value onto unusual ones. So evaluating scripts in isolation is deceptive: what issues is the anticipated utilization sample. A coverage that appears extra environment friendly underneath P2WSH assuming equal use of each path should be extra environment friendly in Taproot in follow. For some use circumstances, switching to Taproot may save kilobytes of onchain knowledge a month!
In actual fact one spending path could also be so seemingly as to be represented by the Taproot inside key. This is able to make spending extra space environment friendly than every other (safe) output sort obtainable, whereas doubtlessly nonetheless necessitating an OP_IF in a single spending path deep down the Merkle tree. This function of Taproot highlights but one more reason why P2WSH will not be a alternative for Taproot. Customers might rely of their Script on options that are completely obtainable in Taproot, akin to protocols leveraging Schnorr signatures.
Lastly, Taproot utilization comes with a preferable set of externalities for the community than P2WSH. For this utilization, P2WSH imposes extra burden on validating nodes than Taproot as a result of its signature hashing is quadratic within the dimension of the witness script. On this regard, Taproot permits optimizations that relieve burden on validating nodes (batch validation). Apart from prices to validating nodes, Taproot additionally incentivizes to develop all outputs’ anonymity set by offering a solution to optimize the area effectivity of some spending paths.
To conclude, whether or not an OP_IF in a Taproot leaf is preferable to options is dependent upon various components. These components are finest assessed by the person, who is healthier positioned to grasp their very own circumstances and constraints. It will be doubtful and presumptuous for anybody to assert to know them higher on everybody else’s behalf. That is particularly reckless within the context of a proposal to invalidate them, on condition that Bitcoin growth has traditionally gone to nice lengths to keep away from proposing consensus modifications that might confiscate some customers’ funds that method.
