Can't make a cappuccino with heavy whipping cream it won't foam. Half and half is doable.

As for why cream or half and half, less sugar and lactose.

Whole milk works fine and is more commonly used

Can’t delete my comment any more, misread the parent comment while it was too early in the morning!

A bit of light cream is so much better in coffee than milk.

Or rather: Is it actually milk you put in coffee? So weird, why not use cream?

A bit of light cream is so much better in coffee than milk.