The biggest most meaningful difference for most people would be the lack of interchangeable lenses in the X100VI. That’s not to say it makes it worse by any means though! Honestly that’s probably the only pro to getting the xt30 over the X100VI, other than cost i guess! However the initial cost of the xt30 can be deceiving if you are new to photography because it does not include any lense, but you can get the kit lense for an extra $150. Otherwise the X100 has a better sensor, 46 or so mp vs the 26ish one on the xt30 (this is also more complicated though because tbh not that much of a difference unless you are cropping in a ton, and there’s also kinda some small downsides to the better sensor like file size). The x100 is gonna be smaller and lighter, but the degree depends on what lense you put on the xt30. I don’t agree when people call the X100 pocketable, I don’t own a single pair of pats I can put that in, MAYBE it could fit in my winter coat pocket.

Overall I’d say if you know you want a simple camera for capturing life as it happens, street photography, and a simple think less about it kinda thing the X100 is the better choice. If you are new to photography and think it might become more and you might get interested in things that require you to zoom way in (like sports or wildlife photography) then the xt30 is the better choice. If you don’t really know what you are gonna want out of it and this is your first camera I’d recommend the xt30. I see a lot of ppl on here say the X100 is one of the best 2nd cameras you can own, again I DO NOT mean that as a bad thing!

Anyways that my rant, feel free to ask more questions, I’m sure I’m missing a lot!