Note how the vowels can be put in different ways as long as they keep their positions. Also forgive my terrible handwriting.
Anyway, let me try:
Let's say you have a upside triangle which is an "L" and you want to write "le" (because why not). You draw the triangle and then you draw just below the triangle the "e" symbol. You can decide if to make it linked to the shape above (sort like a bubble coming out from the bottom in this case) or to keep them separated (so it would be a sort of smiling mouth under the triangle).
I am not sure that for ball pens or pencils, not lifting has any advantage.
You already know the answer if you've ever written anything quickly by hand: it has significant advantages.
E.g.
ක ka
කි ki
කු ku
කෙ ke
කො koကာ - ka ကီ - ki ကူ - ku ကေ - ke ကို - ko ကော - kaw