dear inkuser,
if you have read the other thread (where you also commented earlier today), you should now know that if you want to nicely align things, scribus provides a few helpful tools.
and if you really want to do it with the mouse you simply have to (temporary) switch to a different unit.
ciao
a.l.e
p.s.: and to say "don't use pt for page layout" is akin to saying "don't use knots to measure spaceships speed".
sorry, i could not resist.