Why do we need --force for vue-tsc?

[jemdiggity]

Vue-create by default uses the following for the type-check script:
"type-check": "vue-tsc --build --force",
Using --force is obviously a low slower than no using it. It takes about 12 seconds on my machine for the project I'm working on.
Is there a reason why this flag needs to be included? Can't we just check out of date files?
Thanks in advance.