Hmm, well. ctrl+num could already have global shortcuts assigned. e.g. on my mac, those key combinations are used for switching desktops.
Additonally, there’s a difference between the numbers on the top of the keyboard and the numbers on the number block (on a full size keyboard).
But you are correct, ctrl plus another key can be tricky. These sequences often have special meanings in terminals. It is possible to circumvent possible side effects by erasing the default sequence for a key combination and re-assign them. Unfortunately terminals often do not only adhere to a standard, but also implement their own stuff, which makes it a hit and miss when dealing with this.