Perhaps part of it depends on what your background is. If you’ve grown up immersed in Christianity/Catholicism, it’s easier to go straight to the OT, because you’ve already absorbed the NT stuff throughout your life. And seeing the reflection in the OT is a familiar thing, and you say, “Ahhh! I’d never thought about that!”
But I think starting in the OT is much harder for someone coming in from an atheistic background, even if it’s the chronologically correct method. Because you don’t read something in Genesis or Exodus and say, “Oh, wow! That’s totally foreshadowing something happening 1200 pages later!”
Instead, you’re more likely to run into a situation where someone says, “See! It says right there, 'Don’t wear mixed fibers! Do YOU wear cotton/poly blends? Huh? Well, let me tell you— it’s against your religion!” And they don’t connect that with the Council of Jerusalem bit that happens in Acts 1300 pages later, where they have to decide whether to continue being Jews who recognize that their Messiah has come, and if pagan converts need to first become Jews before they can become Christians, or if they’re something distinctly different, even if their roots were in Judaism, and they preserve the moral code, even if the cultural code that kept them distinct from their pagan neighbors is no longer mandatory.
