I wouldn’t call it a habit as much as a necessity – Depending on map generation setup (Flat, Hilly or Mountains) and luck, you may very well be forced to do a lot of Horsewagon routes as far as Industry goes early on just to stimulate the economy.
The early trains are very slow, which prevents you from making longer lines.
Passengers and Goods will only travel so far and for so long before refusing your services outright – Especially if there’s a road that lets them go by themselves instead of taking a snaky railroad that takes four times as long to get there.
Incidentally the rivers are always at “sea level”, making them obvious targets for your first couple of train lines for passengers. Putting down a bus line of horse wagons to supply the stations is just common sense.
Once you’ve made some initial investments that have a good return of profit, you can start experimenting with a bit of hill climb – and once the faster trains arrive, longer and more snaky lines.