You are correct, but there is a lot that is omitted due to implication here. It's saying that when you travel, going from airport to airport, the implication is that you frequently remove your shoes, so sandals are convenient for doing so. Without that assumption, there's no other real benefit that sandals provide over shoes.
20+, 30+, 40+ years ago, this sentence would not have carried the same meaning when airport security was not as strict, and people would not have been taking their shoes on and off as much.
EDIT: From the comments, it seems that Japanese people frequently remove their shoes during a flight just as they do in their homes. So the implication of often removing shoes is likely more related to this than to airport security measures.