The difference is that Airtable's core data structure is a relational database whereas Google Sheets' core is a spreadsheet. It's very easy to link to records in other tables in Airtable. Google Sheets does not have the concept of records. You could hack something together, but it just works in Airtable. Airtable shines when you want to have a list X, and then for each item in X, have a list Y. X could be homes, clients, or events, and Y could be rooms, tasks, or guests. In Google Sheets, these types of relationships are awkward to represent.