sighash flags – Why is `SIGHASH_ALL` allowed in taproot when `SIGHASH_DEFAULT` is extra environment friendly?

The existence of SIGHASH_DEFAULT makes SIGHASH_ALL redundant for Taproot, since each produce the identical conduct — besides SIGHASH_DEFAULT saves a byte by being implicit.

Given Bitcoin’s typical deal with minimizing blockspace utilization (e.g. x-only pubkeys, minimal ScriptSig guidelines), why isn’t there a consensus or coverage rule to disallow or discourage SIGHASH_ALL in Taproot signatures?

I’m not suggesting it’s a nasty design selection — I simply wish to perceive the rationale behind permitting the redundant type.

The existence of SIGHASH_DEFAULT makes SIGHASH_ALL redundant for Taproot, since each produce the identical conduct — besides SIGHASH_DEFAULT saves a byte by being implicit.

Given Bitcoin’s typical deal with minimizing blockspace utilization (e.g. x-only pubkeys, minimal ScriptSig guidelines), why isn’t there a consensus or coverage rule to disallow or discourage SIGHASH_ALL in Taproot signatures?

I’m not suggesting it’s a nasty design selection — I simply wish to perceive the rationale behind permitting the redundant type.