In a General-formatted cell, entering e.g. =TODAY() would auto-format it to a date format; =TRUE() to Boolean, etc. That would propagate through (some) functions and calculations, like =IF(1;TODAY()) or =TODAY()-1. On the other hand, =LET(mydate;TODAY();mydate) in a General-tormatted cell would produce e.g. 45634 - i.e., the cell won't assume the respective date format. It would be nice, if the variables of LET would keep the expression's type / format group the same way, and then would propagate it to the function's result.