Difference between "Sequence" and "Object"?

[mbc]

When adding objects to a sequence diagram (either by Ctrl-dragging a class or by using "Object" from the toolbox), they are added as something called "Sequences" in EA.
As far as I can tell, a Sequence is exactly the same as an Object, except that it insists on drawing its lifeline, even when inserted on other types of diagrams.
Sometimes I like to have both a sequence diagram and a collaboration diagram showing the same interaction. And I like using the same instances on both diagrams (because they are diagrams of the same instances). But I don't like the lifelines showing on my collaboration diagram. So I used Change Object Type to change each Sequence element to Object instead. It seems to work perfectly.

So what is the purpose of having something called a Sequence element in EA at all? I am sure there must be a reason!

Mikkel