can's use == operator on checkbox results

can's use == operator on checkbox results

I have a registration form where i am trying to have people select lunch for

Monday
Wednesday
Thursday
Friday
Saturday
Sunday

I made this a checkbox field so they could select which days they want lunch.
Lunch is $10/day

I am trying to add up the number of days they selected and I can't do it.

If I say

input.lunch_days   == "Wednesday"

I get the error

Error in statement at line number 1
The Left expression is of type STRINGLIST and the right expression is of type STRING and the operator == is not valid here

Apparently checkboxes are type STRINGLIST and you need a field that is type BOOL

It would be helpful for many reasons if checkboxes were type BOOL
Radio buttons are type BOOL
so why the differenc?