From my understanding, tables are better to use for pivot tables / other reference data etc.
I think from a data structure perspective, yes, the Transactions sheet is a “table” but if there is some more technical requirement, I’m not aware of it.
I’m not sure it is. For instance, if I referenced a table in an equation or a pivot table, the reference would grow as rows were added to the table. Would you be able to confirm if the Transactions sheet is a table?
In Google Sheets, it depends on how the cells are referenced. There are certain ways to format cell references in Google Sheets formulas so that they’re dynamic and grow as the table grows.
I’d recommend reviewing this guide: