The issue of 'smelly feet' is often raised as an argument against the Shoes-Off rule.
In Western society there seems to be a lot of paranoia about the phenomena of 'smelly feet'. I think this is simply a result of people not removing their shoes very often. Your feet will actually smell a lot less if you remove your shoes regularly. It is unfortunate that we in Britain have not yet reached the civilised heights of Finland, where it is acceptable to remove shoes in business meetings and on trains (not that people do not do so in Britain, but it is frowned upon somewhat).
Nevertheless, I think most people worry too much about this issue. People imagine their feet smell far more than they actually do. I have met very few people who let off much of an aroma after removing their shoes, and most of them were people who did not wash and change their socks regularly.
If people know in advance that they need to remove their shoes, they can make sure they wear clean socks, or even better, bring slippers with them. If they are especially worried about it, they can use some of those fancy foot deoderents.
Feet wil smell a lot less if people wear sandals. Sneakers tend to smell more than leather shoes, though I will admit I often wear sneakers when not in flip flops or crocs.
Some people will say 'I would rather put up with a dirty floor than people's smelly feet.' Well, I guess people decide on their own priorities. However, stinking feet will leave with the guests. A dirty floor will not. Nor will the dust they brought in on their shoes, and that is very bad for your health.