The biggest advantage of the Xeons are that they can support more memory and memory bandwidth than the i7s. That bandwidth difference can be massive when performing operations like building lighting on a large, complex scene, since a typical i7 has two memory channels and around 25GB/s of bandwidth, compare to a typical Xeon which has four or more memory channels and at least double the bandwidth as a result. Xeons are also generally better at handling multi-threaded applications, so you may additionally gain some mileage there.
The Xeon’ are also much more stable / reliable, but this is less of an issue since we’re probablt not really doing anything like protracted hardcore data analysis.
There is a caveat though - if you want to make use of the benefits provided by the Xeon, you need to build the system to support it. You’d want plenty of fast memory and a motherboard that supports it, with plenty of bandwidth. This is an additional cost over the top of an already expensive processor that cannot be avoided, since you’ll not be getting any benefit from it.
Personally, I don’t feel like the potential extra performance boost here and there is really worth the colossal extra investment. Heck, for things like lightmass, you can just setup up one or two cheap additional boxes to act as part of a swarm anyway 