Before AppVolumes got bought and became VMware App Volumes, there was Softricity (which became Microsoft App-V).. the app was actually a thin client to talk to a terminal server running the app in a container on a server. Office "installs" in 1 second because it's already "installed" on the app server. The next iteration was AppVolumes streams already installed apps like "Linux snaps" on-demand for Windows to do away with the separate terminal server.
MS Office and most popular multiplayer games are the 2 biggest hurdles for Linux adoption at the moment.
She is not a power user. Working inside a container running Windows just to display MS Word introduces complexity. separate file systems, etc. Sometimes the abstraction breaks, and you "fall out" of the app and end up staring at a Windows environment. It is very confusing for a layperson. On top of that, the RAM overhead was significant for her older laptop.
She is a kindergarten teacher. The last thing she can use is friction on her laptop.
We didn't try LibreOffice. I'm familiar with it, but the learning curve/transition is just too much friction. They also share a lot of documents with colleagues. I don't know the current state of compatibility between MS Office and LibreOffice, but I recall layouts breaking regularly. She also has a library of templates originally created in MS Office.