Hi there,
It looks like there’s some duplicate functionality between Jetpack and Smush – both optimize images, for example, but reading through their plugin description it appears Smush optimizes images at the moment you upload them to your media library, so the optimized version is what’s actually uploaded. Jetpack, on the other hand, makes no changes to the actual file in your library, but instead copies the image to our servers, creates several optimized and compressed copies at different sizes there, and then serve those via our CDN when someone views your site.
So it probably won’t cause any conflicts, and I don’t see any prior reports in either this forum or the Smush forum that indicate differently, so you should be okay to use both. Depending on what features you feel you actually need, you might not need both, though.
I would recommend that you don’t run Jetpack’s and Smush’s Lazy Load images feature at the same time, as I can imagine that causing a problem. But with Jetpack you can use the Site Accelerator without enabling lazy load images, and it looks like you can disable that with Smush as well, so you can decide which one works best for you.
