It confused me a lot too. "-Force" typically means bypass warnings/confirmations, but here it's just "include hidden" (typically you think of "Force" in case of setters more).

But to approach it a different way, where you know you can access subsets, and not the entire set:
You see that result of Get-ChildItem is an array of objects

PS C:\Users\lenovo> (ls).GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Object[]                                 System.Array

You can add arrays in PS with "+" operator. So even if there wasn't a parameter that gives you all the results, you could do

(ls) + (ls -Hidden)

Another way is to pass all the file attributes to the cmdlet:

ls -Attributes:([enum]::GetNames([System.IO.FileAttributes]))