Walking has its place, beginners and ultra-runners.
Nothing wrong with some walking for a newcomer to running.
I know two older guys that can power hike sub 13:00 pace effortlessly (no they do not look like they are race walking) - faster than most hobby joggers. Both are / where ultra-runners that where actually fairly fast at one time. They are the poster children for walking being a drug - no excuse too lame for these two to walk, especially when they are together. One just completed the Grand Slam of Ultrarunning (I am sure he walked a ton) and the other believes he could do the Rocky Raccoon 100 miler in sub 24hours by just walking. I actually believe he could do it.