I don’t think locking down slashes support calls because you will now receive support requests anytime someone wants to install something and actually have a good business reason to do so.
Consider the ones you don't get: ones where PCs have to be wiped from customization gone wrong, politics and productivity police calls - "Why is Bob gaming?", "Why is Alice on Discord?".
It's about the transition from artisanal hand-configuration to mass-produced fleet standards, and diverting exceptional behavior and customizations somewhere else.
Coupled with protection against executing unknown executables this also actually helps with security. It's not like (most) users know which exe is potentially a trojan.
If you don’t want exceptional behavior, that’s exactly what you’ll get. In more than one way.
Alice is on Discord because half of the products the company uses now give more or less direct access to their devs through Discord