I think there's a subtle difference between your interpretation and the original text. Your interpretation makes the incompleteness of the answer the main point and focus of the sentence, while in the original text, the incompleteness is just an aside. In fact, the whole second half of the sentence is more or less an aside.
Asides / Parenthetical Expressions
As for what an aside is -- the term "aside" is equivalent to "parenthetical expression". The below excerpt does a good job of explaining the purpose of asides:
A parenthetical expression is a phrase or clause that’s inserted
within—in effect, it interrupts—another phrase or clause. The larger
structure is complete without the smaller structure, which could be an
adverb clause, as in the following four examples, or an added comment
or remark that has no syntactic function in the clause. [...] The idea
is to add information rather quietly (a brief definition or comment,
for example), so as not to distract the reader from the rest of the
Reinterpreting the example sentence
A more faithful re-interpretation of the text would be something like:
Physical science gives an answer to this question. True, that answer is somewhat incomplete and in part still very hypothetical, but it [the answer] is still deserving of respect, so far as it [the answer] goes.
(words in brackets are just added for clarification of what "it" is referring to)
Edit: added link/quote and explanations of asides