[DayDollar]

In many scripting languages this is not the case, and you are ever only passing around references. Python comes to mind.

Lots of people obviously have a problem with this as it deeply different from the algebra derived assignment syntax.

local a = b creates a local copy, but even then, its not a deepcopy, containing references to other tables.

[kzrdude]

python has both .copy() methods and a copy module. That's not to highlight Python's strengths, but an indication that it's a complex topic in Python - it has footguns here. The copy module might even do the wrong thing for a given object.

[naniwaduni]

The algebra-derived assignment syntax kind of falls apart with mutation anyway.