Use Tables or Worksheets in Excel -how to edit the table after its a live scenario?

I have had more success with (excel) Tables than worksheets. Make seems to like the headers.
They also seem more intuitive to me.

Is it best practice to use tables or sheets for say order details of an etsy shop?

After successfully starting a live scenario - with 2000 lines of data - is it possible to add columns to the start or end of the table? Or insert them in the middle? And not lose all the data? Or mapping? Or corrupt the scenario?

Bonus Q: what is the adv / dis of selecting map? Sometimes I turn this on on excel module and it helps it find the new colum titles i changed. Often Make wont pick up changes to column names.
Im such a novice. Sorry!