Are there any drawbacks of using static variables?

[david_2018]

@madmark2150

So because the Harvard architecture, we can't easily put string constants like "Hello World" in program space.

Easily is a matter of opinion, once you get used to how to do it storing string constants in program memory is not difficult.

@tjaekel

STATIC variables are often just used for large memory where not so much auto/dynamic
stack variable space is available - my approach to avoid "stack issues": put static in front of large local variables... (ugly)

I don't quite understand that reasoning. The same memory (ram) is used for static variables and stack space, so using a static variable reduces available stack space. Potentially you will even greatly reduce available stack space by unnecessarily declaring variables as static, since that memory is permanently allocated, while using local variable allocated on the stack allows the same pool of memory to be reused for variable in multiple functions.