Depends what their long term goals are. If their goal is a mortgage or getting married and having a family, better save when young, travel when a little older. If not, go for it!
Many "elderly" people or late middle aged people are sprightly enough to travel still these days. I knew a couple who were well into their 80s when they stopped travelling. I think they started 20 years before then. They went everywhere! Before that they were working and raising their kids.
I suspect a lot of young people don't have the funds these days, even those who aren't tied to mortgage commitments or paying off weddings at all. That said, working while traveling more likely an option when younger.