Typical cursive is a form of connected writing originally designed for pens and quills with flexible nibs. Letters like ℓ have loops because when writing with these tools the downstroke is thicker than the upstroke. The result is a recognizable lowercase L with a thin stroke on the side. It's easy to read even if you've never had to before.

This form of writing was dated as soon as the ballpoint pen was invented, which was in the 19th century. Writing it with a pencil makes even less sense. By tradition we have clung to this terrible writing style instead of introducing something more sensible and modern like italic cursive, which is connected but without loops.