The idea that you can log into any PC and your local desktop and documents all appear seems really nice, but the implementation weeds are nasty: I tell people to store things they want to access on multiple computers on a network share, and we replicate basically nothing between client PCs.
Outlook also likes to download a large chunk of a user's mail archive locally each time you open it on a PC, but you can configure it a bit, and Outlook generally "works fine" while downloading. I suspect it gets hairier at DOD scale though.
At my company people would remotely log in on Sunday evenings to avoid the hou long wait while a few hundred gigs get copied across the network. Why not chnage the location of the local repo, you ask? Of course our machines are locked down and we have no access to the local drive...
I found out this is a thing when Chrome and Firefox started to put their files in the user's home directory by default. If that has to traverse a network - and who knows where all that data is coming from or how fast the internet connection is - that can take a long time.