What terrible advice. Your public variables are so much easier to refactor if/when your data changes when you have simple accessors methods around them. Having accessors for data have saved my ass multiple times when I've had to do things such as a) migrate the data transparently b) remove data and use computation instead c) debug reads or writes of data.

The last point, sure you can have a breakpoint on a memory address but if you have a getter/setter method its trivial to put a breakpoint in there, but I bet that if you have to set a memory brekapoint you have to waste time googling how do that (at least with GDB)

Raw data POD type structs are useful but only when the scope is limited.