I agree it can be used as both. We usually make the 'basil/pine nut' one but for certain dishes make variations - sun dried tomatoes, walnuts, some parsley orsome spinach or other herbs, other nuts, etc.

If you do a Search here on TKL you'll find many recipes for pesto and for uses.

One of fastest is for pasta - cook your pasta - reserve a half cup or so of cooking liquid in case you need it. Toss pasta with pesto - sprinkle with grated Parmesan ... if needed, add a bit of the reserved cooking liquid.

Sometimes we mix pesto with mayonnaise or sour cream or plain yogurt (or mixture of 2 of these) to make a dressing for pasta salads -very good with tortellini, cooked chicken pieces, sugar snap peas.

You can mix a bit with crumbled feta, or goat cheese or whatever - maybe something else and stuff in a slit/pocket in chicken or pork. Brush surface with some diluted (with olive oil) pesto and grill.

A friend often sautes fish - shrimp,etc in a bit of pesto -- instead of butter or oil. Saves having to 'season'.

Great in dips, spreads, apptizers. Spread on crusty sourdough, etc. breads- to make a sandwich - adding proscuitto, provolone, roasted red peppers or whatever. I've used it in bread dough. It's a good pizza topping.

If you have fresh mozzarella - it is good in the sliced tomato/sliced fresh mozzarella fresh basil 'salad/appetizer'.
And so on. Whatever you like - you'll find a zillion uses for it!