Title says it all.
compare your string values going in and coming out via a select tool.
Autofield's description is literally that it does what you asked for. I do not believe it converts numbers directly to bytes but ints can be converted to bytes with a select tool and other numbers must be first turned into ints and then bytes.
from tool description:
Use Auto Field to read through all of the records of an input and set the field type to the smallest possible size relative to the data contained within the column.
The tool correctly assigns a numeric field to a string data type where any record starts with zero and not a number.
https://help.alteryx.com/current/designer/auto-field-tool
I don't see how autofield does this.
It does not change the byte size in a downstream select nor does it give you a message box that i see
