The reason its not seen as clear cut is when research has been done such a change changes a whole host of other behaviours of people e.g. where they choose to live or even how they travel.
For example, a policy that allows hybrid working or fully remote working might lead a portion of employees to move from a city centre where car ownership is low to a suburb where it is high. So you might replace a 5-day a week short commute by public transport with a 2-day a week long commute by car which would generate more emissions. This is more than just a hypothetical and has been observed in some cases.
It's also worth just noting that whilst digital infrastructure at current levels is usually less carbon intensive than any amount of carbon intensive travel it does have a cost and that the trajectory to more and more intensive technologies is increasing that impact (e.g. blockchain and modern AI techniques)
Lastly, there are efficiencies of scale for heating and cooling that might be achieved in offices which might outweigh the transport costs. This is true where I am partly because offices have been brought up to modern spec by regulation where housing has been let go: being more draughty and less insulated.
Personally, though my take is that whilst these second order effects are super important to look at (since in the short term will be linked to real world emissions) I think they are probably best thought of as ways of showcasing issues in other sectors that need tackling serpately (e.g. the suburbs needing to transition away from carbon intensive travel and land use policies to ensure that we don't lose the necessary density of our urban environments).
The only time I think it would be important as an assessment of a particular policy is when some cost is intrinsic to that change. Say, for example that the only way home working could function for a particular use case was by using some sort of energy intensive block chain system for authenticity and the additional emissions costs outweighed the benefits of avoided travel.
At least for North America, it's really more a story about the housing crisis and fake-rural suburban sprawl than anything.
Sure, you'll get those doe-eyed types -- usually wealthy folks -- that talk about wanting to quietly live out in the countryside with no one and nothing anywhere near to them. But most people don't want to move somewhere so inconvenient, at least not if they have to actually face the disadvantages of it (like unpaved roads, no municipal sewer/water, unreliable internet/electric, long trips to highway big box stores for even the most basic necessities, etc).
When push comes to shove, most want to live in an actual town. Maybe not a huge metropolis, but a place where you have knowable neighbors, convenient shops, basic city services, restaurants and bars, and all those things. A place where you don't have to fight through a 30 minute highway commute just to get a loaf of bread.
But they can't. We have vanishingly few functional towns. Instead, we mostly have massive cities with tons of amenities but which you can't afford to live in, vast sprawling "suburbs" and "exurbs" of said cities that are completely parasitically dependent on their host city to function and aren't places in their own right, "small towns" which are just weird little growths off of an interstate offramp with no meaningful local industry of their own.
When your choice is an unaffordable metropolis, a "small town" which is nothing but national chains huddled around a place a major road crosses a highway, or the inconvenient but affordable "exurbs"/countryside, the comparison gets bad. It's all just a byproduct of our incredibly bad housing policy -- policies that favor national builders spawning whole subdevelopments out of thin air over local infill, policies that make it nearly impossible to build modest density/mixed used places, policies that care more about the financial products the housing underwrites than actually homes. Policies that rob people of choice and instead push them to all live a weird, unnatural way that violates thousands, tens of thousands of years of human development.
These advantages you see in office commutes... aren't advantages of office commutes. They're advantages of good urban living. And the idea that you wouldn't live in a city if not for a job forcing you has such intense American energy I bet it drives a lifted Ford F150 covered in bad eagle decals.
What's this, a shockingly well-informed conversation about housing policy, building patterns, transportation networks, and carbon emissions? I'm here for it!