I followed a Jaime Oliver recipe for curry, which started with grating onion, ginger and garlic. I liked the curry, but grating an onion is a miserable job. He said that technique unlocked the onion's 'sweetness'. How much difference do you think I'd notice if I used a food processor?
A food processor will do a very similar job, some food processors even have a grating accessory you can buy. I wouldn't worry about the modest difference in flavour.