A bunch of American companies have international traveling employees with US visas (immigrant or non-immigrant visas) or (perhaps less likely to be impacted) US permanent residence permits that are potentially impacted by this travel ban. Some of those who live in the US but are or were outside of the country have been rushing back (to try to get into the US) upon hearing of this executive order being signed.
Given some such people have families with young kids who live in the US, traveling abroad and being hit by a travel ban while outside of the country can seriously tear apart a law-abiding family. It's also likely to damage some careers.