Expression (in line chart) vs variable setting

[becki_kain]

(new to qlik,  this is week 2 of learning, for me) 🙂

i've been using, since that was all i knew, expressions, as columns, in line charts and then doing things like making another expression of "columnAA/columnBB" to set values but the I knew I'd have to hide all the intermediate columns, from view, for the final dashboard.  Then i figured out setting variables with the same expressions.  is there an advantage in speed or anything else , outside of not having to hide extra columns, in using many variables over using many columns, for the same calculations?

thanks

becki kain