You are correct, setting the points to .020" is usually "close enough". Setting the points precisely requires one of the timing fixture tools, a decent analog ohm meter, and a timing light. There are two "timing marks" on the mag plate, one mark is used for "new points", the other is used for an existing set of points, there are two marks on the flywheel as well, one for each set of points. The extra timing mark is used for new points to account for initial rubbing block wear. Sometimes it is recommended to set new points at .022" for this same reason.
So, is all this extra effort "worth it"? I guess I would say that if you have the correct timing fixture, than it is definitely worth spending a few extra minutes to set the points precisely. Setting the points precisely will probably help the engine idle as close to perfectly as it can. But, there are some factors to consider before spending the money on a fixture and extra time doing the procedure precisely. First, the point timing is affecting by any sideways slop in the mag plate or upper crank bearing/bushing. In other words, spending extra time and money on an engine with a sloppy mag plate might not be worth the extra effort.
You can still check the point timing with a timing light after simply "setting the points to .020", to see if the timing is correct/close enough.