You mean on-prem or cloud? I know for a fact that my on-prem power supply is flaky - we've had power cuts multiple times, most recently when one (now ex) employee literally pressed the big red button because he wanted the day off.
If I'd been in the cloud at that time, all my users could have taken their laptops to McDonalds and worked happily with access to email, files and phones, rather than sit around a dark office, running down their batteries playing Solitaire...