The people who have been doing the grocery shopping where I work recently started buying
el cheapo chocolate chips. I realize there is a budget and we must mind our food costs, particularly now that the cost of everything is now rising, but the cheap chocolate sucks big time.
Not a lot of people know this, but lots of times, in order to make a product cheaper and to give it a higher melt-point, companies remove the cocoa butter from chocolate and replace it with palm kernel oil - or another type of oil, but palm kernel is the one I've seen mostly. Your first clue that the chocolate isn't real is the name it's called on the package, like this one:

Notice how it says "chocolate flavoured baking chips" not "chocolate chips". That's because these chips aren't real chocolate, since the cocoa butter has been removed. Here is the list of ingredients:

You can't call something chocolate that isn't chocolate. Note that these chocolate chips are made with cocoa powder (also note, incidentally, that they misspelled vanilla - gr), which chocolate is made from but is not actually chocolate. France has laws about this stuff, you know!
Anyway, here are some of the downsides of using this kind of chocolate, which has a name:
compound chocolate.
- it's grainy on the tongue and lacks chocolate's smooth texture
- it lacks flavour, or is too sweet
- it doesn't pipe well at all
- it actually sticks to pans quite a bit, as seen in this picture I took at work last week:

While this may not look dramatic to you, it actually is a pain in the ass because it makes de-panning muffins and cookies much more difficult. Unfortunately, I lost four muffins last week because the fake chocolate chips stuck to the pans and wouldn't release upon cooling (OK, it wasn't a complete loss; I got to munch on chocolatey muffins during my shift, but still...).
The moral of the story: if you have to pinch pennies when baking, do it with another ingredient, not with the chocolate!