Not a problem if you are extra careful with your belongings, wallet, camera gear, mobile phone, etc. As a tourist, one tends to be relaxed watching around, and usually it's when one of the hundreds pickpockets around attacks. And this is just one of the possible issues there.
This is a problem that is basically true anywhere. Sure, some places are safer than others, but in the end, it doesn't take much to be aware of one's surroundings when travelling. It is really easy to spot the pickpockets around. If a place is worthy of any tourism, there will be some sort of scammer, pickpocket, mugger or thief. It's an unfortunate side-effect of tourism.
As you have said correctly, some places worse than others, BCN is on the bad side. Anyway, have a nice trip there!
I’m currently on a trip traveling across Spain. I brought my X-H1 with 10-24, 18-55, and 35 f/2. So far in Madrid the 10-24 is the only lens I’ve used. The streets are narrow and plazas are very crowded. It’s also very helpful for interiors. It obviously depends to some extent on your shooting/subject preferences, but I think that you’d regret not bringing the 10-24. Just use the camera's electronic level and keep the camera horizontal as much as possible and then crop in post if needed.
Understanding the concerns you have about Paris I have to comment that it is truly my favorite city in Europe. I've lived in different places in Europe for a total of 4 years, been to Paris 5 times, and would go back tomorrow in a heartbeat. When I took my kids to Europe for a 6 week trip Paris was one of their highlights.
I think if you want to travel light - the 10-24 on the camera and 50-230mm in the bag would be good options.
Well, there are the smaller and cheaper XF16 f2.8 or XC15-45.
Both Architecture and Family.
Would the 16/2.8 be too similar of focal length to the 18-55?
Set your 10-24 to 16 and the 18 to decide for yourself.
Barcelona is worth visiting, but also has a bad reputation for theft, and the police for ignoring it. (That's reputation, not my personal experience.) Paris seems to me less so, and you have more space around you there.
I noticed that nearly all my shots with the 18-55 were either at 18 or 55. I was always trying to get wider or narrower. So, the last time I went to Europe I took just the 10-24 and the 50-230. It worked really well and I didn’t miss the gap between 24 and 50. Next time I think I might add the 35f1.4 just to have something with a fast aperture along for evenings, etc.
