There are sometimes some strange issues with office construction.
There might be no plumbing in the locations people will want for toilets and baths and kitchens in the individual suites away from the core of the building. Same goes for retrofitted laundry facilities.
HVAC systems (in the US anyways) are often centrallized and might need a lot of retrofitting to make it work like a condo/apartment.
Kitchen ventilation
Windows might not open, can’t get to a fresh air source
Aside from that stuff, the issue of empty office buildings while we are experiencing unsustainable housing markets is begging for a solution to address the demand.
There will probably be a handy sum to be earned for construction companies who get efficient at conversions.