The i7 model has a 400mhz higher base clock and a 500mhz higher turbo clock, along with 4MB cache instead of 3MB. That's enough of a boost to be noticeable, but it's still a fairly old dual core processor. It would be well behind anything that's made in more recent years.
If it's an easy upgrade and you can afford it, I don't see why not. But 2015s are going for surprisingly good prices in the used market these days, they might be worth looking into if you can find a good one.