Dear Xara...

Flow Lines 1 to 4 are the same template other than lining up one End (Flow Line 4) or changing to a Dashed Line (Flow Line 2).
Why stop there? You have created 16 End styles so you could have shown them all as boxed, cornered, zigged and zagged, making 1,024 in all.

Instead, you have left doubt in the designer's mind whether to use template one through four might result in picking the wrong one.
Revel in the variety you have created so we can.

Flow lines they are not.

With two corners, I cannot create a complex flow across a drawing with two corners.
A smart flow line would allow another corner to be added, repeatedly.

I find it near impossible to butt an end to the butted end of another line.
Smart shapes do not Snap to Objects in the same way as other Xara objects.

Squishing or Squashing a Flow Line breaks its rotation capability.