Celery is a vital ingredient in the Italian sofritto and the French mire-poix. For the former, diced celery, onion, and garlic, usually followed by chopped parseley in prodigious quantities of olive oil. For the latter, diced celery, onions, and carrots in butter. These form the base for numerous delicious soups and sauces.

As for raw celery, well, I have not much use for it. However, its flavours become vivid and even spicy when cooked. I have tremendous respect for it as a flavouring agent in vegetable stocks let alone in a sofritto or mire-poix.