An invisible zip costs more than a regular zip, so why bother with one that's more expensive? The short answer is it depends on the appearance you want for your finished garment.
A regular zip has a chunky head and pull tab, and the zipper teeth are visible unless covered by a fly or a flap formed from the seam allowance.
set at centre back of skirt.
Once I learned how to insert an invisible zipper, I developed three reasons for preferring its use.
1) I like to keep the lines of the garment uninterrupted by 'housekeeping'.
2) On garments like chemises that have a side zip that sits close to the armpit, the less bulky the tab the more comfortable the wearer will be.
3) I've noticed that exposed zip pulls on regular zips (usually skirts and jackets) quickly lose their pristine paint job. When grey metal shows through the paint (see image below), the garment looks old and worn. I make garments to last, so I want zips in them that will uphold the family honour.