From what I understand having read the anecdotes here about Bakken's book and muscle tone, it is absolutely not necessary for your average hobby Jogger.
In my experience working with runners in the gym, it is easy to tell when someone is unrecovered from overtraining or excessive load for example (or many other things like lack of sleep, stress, drinking, etc.) Their muscles DO present differently and movement in the gym and outside will be subjectively more difficult. But that can also easily be avoided if you just do what has been laid out in sirpoc's book and run TRULY easy, don't overcook sub-T and progress slowly. If you're lifting, do it on the sub-T days so easy days are easy, which Bakken talks about in his book (I think)
I personally find muscle tone very interesting from what I've read here and will definitely be picking up a copy of the book to investigate. But I'm also aspiring to work clinically in sports rehab and physiology so it's a bit more up my lane. I would say the intricacies of it might be a bit beyond the needs of the hobby jogging population unless you're a nerd like me, though. Just my 2 cents.