Same reasons why you shouldn’t run a website from home. Data centers have redundant supplies of power, internet and employees standing by 24/7 making sure servers are up and running correctly. The data center near me has it’s main source of electricity, a secondary source of electricity and then 4 massive back up diesel generators as a backup to their backup.
Now that’s not to say you couldn’t run this from home but you have to make sure your power setup is solid (put your servers on a UPS), have a really good internet connection with low latency and finally maintain the server / computer for any issues that may arise and constantly monitor it that it is still online.
I’ve ran computers and different setups from my home office before and I can tell you now the headache and stress is almost not worth it. You never think your electricity or internet will go out but they inevitably will go out and you need a plan in place that takes over within seconds.