The overnight bus is the classic budget manoeuvre because it removes a night of accommodation from the trip. The saving is real and it carries costs that are easy to overlook.
The arithmetic is genuinely favourable
A long-distance night service replaces both a day of travel and a night of lodging, so the fair comparison is against a daytime fare plus a bed rather than against a fare alone.
On routes of eight hours or more, that combination frequently beats a daytime bus with an extra hostel night, sometimes by a considerable margin.
It also preserves daylight at the destination, which on a short trip is worth more than the cash saving to most travellers making the choice.
Sleep quality decides the outcome
A traveller who sleeps reasonably arrives functional, while one who does not loses most of the following day, which cancels the saving entirely.
Seat recline, legroom, whether there is a footrest, and how many stops the service makes are the practical determinants, and they differ hugely between operators on the same route.
Premium overnight services with wide reclining seats cost more and are usually better value on routes long enough for the quality of sleep to matter.
Arrival timing is often the hidden problem
Night buses commonly arrive very early, well before any hotel will check a guest in, leaving several hours to fill with luggage and no rest available.
Cities with a station café culture absorb this easily; others do not, and an arrival at five in the morning in an unfamiliar district is the least comfortable part of the journey.
Booking accommodation from the previous night, so the room is ready on arrival, converts the saving into a smaller one but removes the problem completely.
Security requires a different routine
Bags stored in the hold are generally accessible at stops along the way, so anything valuable belongs in a small bag kept physically attached while sleeping.
Passengers board and leave through the night, which means the cabin is not a closed environment and a bag left on an adjacent empty seat is exposed.
Experienced overnight travellers keep documents, money and electronics in one small item and treat everything else as replaceable, which simplifies every intermediate stop.
Some routes suit it and others do not
The manoeuvre works best on distances that fill a night: too short and the traveller is woken after four hours, too long and the second day is spent aboard as well.
Mountain and coastal routes with heavy curves produce poor sleep regardless of the seat, and are usually better travelled by day for the view anyway.
Where a rail alternative with couchettes exists, the comparison is worth making, since a flat berth changes the sleep equation more than any bus seat can.