For the practical reason that I no longer drive and do not fly.
Aside from that, my motivation for taking the train (instead of just staying home and never traveling) always was that it was a reliable, comfortable, and worry-free mode of transportation.
For short distances on the NEC, I knew the conductors would alert me to when my stop was coming up, tell me which doors would open, and help me with my suitcase and getting down the steps if needed.
For long distances, the minute I settled into my roomette, had my ticket scanned, and met my SCA, I knew I did not have to worry about anything and could just relax.
This is still true of the short distances on the NEC,
Unfortunately, with Amtrak putting sleeper passengers into coach, plus cutting out a train here and there with little warning—both of which may have reasonable explanations but are unnerving to someone like me who takes the train for predictability and reliability —I am now afraid of taking the train out of the Northeast.