There are some unexpected work conditions, where a self-built switcher can become really dangerous. That's something for a really experienced person only!!
Absolutely, and do not forget that a self-built switcher is very likely to put the input voltage on the output = whatever it supplies (micro, interfaces and LED etc.) destroyed.

Do not rely on a "test with a resistor load" that say nothing.

Succesful testing does not prove the abscence of bugs, it proves the abscence of known bugs.

Ertan, Kai blew a switcher, my engineer could not build a 100% reliable one in 6 months, are you getting the point?

Erik