If the parameter is definitely unused, [[maybe_unused]] is not particularly useful, unnamed parameters and comments work just fine for that.
[[maybe_unused]] is mostly useful for things that are potentially unused, like in
void fun(int i, int j) {
assert(i < j);
// j not used here anymore
}
This can’t be handled with unnamed parameters, but if NDEBUG is defined, will produce a warning because j is unused.
Similar situations can occur when a parameter is only used for (potentially disabled) logging.