Well, you can take it because it's cheaper than flying. Prices are comparable to the dirtiest, cheapiest dirt cheap flights with no checked baggage, carry-ons etc., but with more space, free wifi + (often) functional mobile data, better amenities, no TSA, and all the luggage you can carry. It's amazing being able to bring a whole guitar in a gig bag without having to worry about it at all.

The romance of it is wonderful too, but even from a purely practical standpoint the only real downsides are the slow speed and inconsistent arrival times.