Reacher's world is pre-smartphone for most of it. That's a key part of the chronology. The early 2000s books have him using phone booths and phone books. As you move into the 2010s in the timeline, cell phones become more common, changing how plots work. Reading in order lets you see that technological shift organically, which is a neat side benefit.
The list is a commitment, but each book is a quick, propulsive read. You're not signing up for 'War and Peace' 28 times. You're signing up for a consistently engaging thriller that you can finish in a few sittings. That makes the long list less daunting.