The two proposed senses of mithl change the legal method. Resemblance of form calls for identifying an appropriately comparable animal; equivalence of value gives priority to monetary assessment.
Jurists have discussed the issue differently. It is therefore inaccurate to present either application as a universally agreed, undisputed interpretation.
The core question is which notion of likeness is better supported by the relevant wording, usage, and legal evidence.
Principle: selecting an intended meaning requires reasoning; the mere existence of several possible senses does not extend one legal command over all of them.