The small toiletries I just buy on arrival. As a (fragrant) side note, I've haven't used soap or shampoo for two years.
I think I bought it at Walmart for maybe $20 bucks. It might be the highest EV purchase I've ever made.
The same reason we do a lot of unnecessary things: advertising. Soap manufacturers spent many years promoting the idea that unless you bathed daily using soap everywhere you would be more smelly than a skunk and people would shun you.
That's also why we use mouthwash daily, by the way. Listerine was first sold to consumers as a floor cleaner. To boost sales the manufacturer invented the word "halitosis" (because that makes it sound much more serious than "bad breath") and promoted Listerine as the way to prevent it using scary ads proclaiming that you might not even know you have it but your friends will know. It worked, and in under a decade revenue went up by nearly two orders of magnitude.
There's an excellent "Adam Ruins Everything" episode on hygiene that goes over these things and more.
I have had occasion to be near people who believe as you do on a regular basis, and yes — they have a strong odour. I do not find it pleasant, although I suppose it is not completely and totally unpleasant either. It is definitely present, and not something I would choose to invite into my own personal space.
And whatever one calls bad breath, it can be so bad as to cause one to retch.
I won't propose that modern washing & mouthwash measures are the best preventatives to these issues, but I do insist that these are actual issues.