For me, wearing tzitzis out serves as a constant reminder of who I am, and what I am supposed to do, just as wearing a kippah at work or on the street does. The only situation in which I tuck them in is if I visit a cemetery.
I certainly don’t look down on anyone who tucks them in, or chooses to do so while at work. If I were in corporate sales, I would be meeting people who never saw a Jew with tzitzis before, and who wouldn’t be able to get past that.