Don't you feel happy when you sweat after a workout? Similarly, a professor feels happy with "messy" chalk all over his hands after a class.
I find it much easier to write using a chalk than a marker. It gives more control. Just like writing with a pencil gives more control than writing with a pen. Moreover, I can easily erase something by hand if I have to make a small correction when I am writing with a chalk and can easily wash it off later on, which is much harder with a marker. Moreover, I don't like the smell of chemicals in a marker. Chalk has no bad odor.
Considering the finances, markers are much more expensive than chalk.
I like to blog about various topics ranging from education in IITs to social issues in India and US. All opinions and views presented here are my own and not of my employer.