Well it it depends on you. Do you want to eat it and do you like the taste?
The oil in the can is safe to eat. However, the oil will taste more fishy than the oil from your cupboard as it has been in contact with the sardines.
If you are not sure if you want to eat the oil you can do what my mum does.
My mum generously “butters” her bread with some of the oil from the can as she really enjoys the flavour. Then she mashes sardines (bones included). Adds finely chopped raw onion, a little bit of green chilli, salt and pepper. Stirs it a bit then piles it atop her crusty bread. Her favourite is a baguette. Then she sits back and enjoys it with a cup of tea.
If you are thinking I don’t want to eat the oil directly there are a few other options. You can store the oil in the fridge in a container for 3-4 days and use it as:
Salad dressing - sardine oil, lemon, salt (if desired) and pepper. Try a sardine salad with olives and capers (if you like)
Oil in cooking - Cook your onions in this oil and add some garlic, ginger and tomatoes (fresh or tinned), salt and pepper. This will make a basic tomato sauce you can use for pasta, with chicken or vegetables.
Dipping sauce - Bring the restaurant feel home and serve sardine oil with its savoury infused sardine taste with focaccia or another bread of your choice, You can make a dipping sauce by adding chilli flakes (if you like), lemon juice, oregano, basil, parsley, pepper and salt.