I'd indeed say it costs more than most people are willing to pay.
That said, a sleeper car on Amtrak gets you: a flat surface to lie down on, your own toilet (note the toilet is just there in the roomette, next to the bunk, prison style), access to a shower (your own shower in the rooms, one per car for the roomettes), access to the first class lounges, and includes meals in the dining car.
Rooms have a slightly wider lower bunk versus roomettes to sleep 2 (skinny) people and an enclosed toilet so you don't lose mystery from your romantic or work relationships. Roomettes are too small for a first world prison cell but have the beds oriented parallel to the direction of travel, which many people find more comfortable -- the rocking of the train is more soothing and less jarring.
If you have the time, don't mind paying four-star hotel prices for a two-star experience, and hate flying or have a medical condition that makes it infeasible you should definitely consider it.
Or, if you're on this site, it's a great excuse to sit in a small room with a view and not talk to anyone for several days, just read, write and program.