Notice the choice in foods. Is marinating meat hard? No. Does it take a whole lot of forethought and/or time? Yes. As compared to finely dicing onions, which is

Notice the choice in foods. Is marinating meat hard? No. Does it take a whole lot of forethought and/or time? Yes. As compared to finely dicing onions, which is probably more difficult to do well than a simple marinade but also a lot faster.