While I (think) understand the sentiment (ergonomics and practicality), it is still worth studying Lisp for a number of reasons. In particular, I would recommend to everyone to study Lisp 1.5 [1] to appreciate how an entire universe of programming languages can be bootstrapped with just a few primitives and equations.
It is true that, today, we have a vast array of impressive tools at our disposal, from parser combinators and generators, code generators to entire language workbenches with projectional editing capabilities. However, if one were to design a language for any reason, having a deep understanding of the expressiveness of computational models such as the lambda calculus would certainly be an "advantage" (especially for those who end up having to use the language): A Lisp/Scheme is as close to interactive lambda calculus as it gets. From there on, one can learn about implementing different evaluation strategies, scoping rules and continuations (William Byrd's "The Most Beautiful Program Ever Written" [2] also to mind).
Now, I am not sure whether homoiconicity tends to lead people astray. It is true that is it not strictly necessary to make a language extensible (e.g., Smalltalk has no macros and is very extensible due to its powerful meta-object protocol and an elegant syntax for closures), but it's still worth studying the concept. For example, writing a metaintpreter in Prolog [3] is surprisingly easy because of its homoiconicity.
[1] https://softwarepreservation.computerhistory.org/LISP/book/L...