Long distance walking exacerbates the health benefits gained from walking, provided that the walker works up to long distances and doesn’t over-do it. Health benefits include a reduction of body fat, increased bone density, reduced cholesterol, increased flexibility and lowered blood pressure. All of this is without excess pressure on the joints.
Along with the above, an older guy gets better mobility and increased relaxation. And he could get that with 30-45 minutes every day or even a few times a week. The only downside I see is too much walking might reduce muscular development. Look how thin long distance runners are? It’s like long distance running or walking shreds muscles. I think, however, and I could be wrong, leisurely walks between 30 minutes and an hour and a half would not interfere with muscular retention.
Why would it matter if a lot of walking shredded some muscles?
My thinking is with sarcopenia knocking at your door and wasting your muscles, and your strength every passing year, it might be a good idea to hold onto some muscle for better strength and independence in you older years.
That said, an older guy would probably do okay if he added resistance training to his long distance walking or running passions.