First of all, I do not see a big difference between logic and mathematics; the latter has just been systematically applied to specific structures.
Also, I'm not sure that the theoretical beauty of programming languages based on math / logic is really worth it to succeed by writing effective, supported code.
Regarding specific issues.
What are the benefits of modeling programming languages or function language in math? What are the benefits of language modeling using formal logic?
Proofs of correctness become much simpler - although it is doubtful whether we will ever get to the point where they become practical for real systems.
Can a general-purpose language betray either logic or mathematics?
Depends on what you mean by "forgo". You can have a language without mathematical operations (although you should get pretty multi-ethnic, Turing machines are the only thing I can think of that doesn't even have an increment or decrease), and you can certainly have one that doesn't care on formalisms (Assembler, C). But I do not think it is possible to have a programming language without logic (although it may be perverse logic, cf. Malbolge )
What are some of the languages that truly demonstrate the benefits of any approach?
Well, if you think that lambda calculus is a form of logic, then Lisp demonstrates its advantages well, since since 1958, a language into which expressive power expresses other languages (but does not cope) has reached.
Then there is Prolog, the only other “serious” language that I know, which is trying to be clearly substantiated in formal logic. And - quelle surprise - it's good at logic and a bit more.
What hardware features make one approach more attractive than another?
Missing. The failure of Lisp Machines proves IMO quite convincingly that compilers + general hardware are more powerful than specialized hardware. However, it can be said that the simulative power of today's system makes languages that completely ignore hardware limitations practical where they were not before.