Do the math. Is the extra speed gained enough to compensate for the extra distance traveled. In the case of a monohull, it often isn't. They just don't make up enough speed to offset the longer distances. A multihull on the other hand generally does.
It probably depends quite a bit on the wind speed as well...
To get to a windward destination 30 NM away....
If sailing at 60˚ off the wind requires you to sail 48 nm... and sailing 45˚ off the wind requires you to sail 42 nm, but sailing at 60˚ allows you to sail at 6 knots vs 4 knots.. then you get 8 hours versus 10.5 hours... so yes, it would be worth it.
If sailing at 60˚ off the wind requires you to sail 48 nm... and sailing 30˚ off the wind requires you to sail 39 nm, but sailing at 60˚ allows you to sail at 7 knots vs 6 knots.. then you get 6.85 hours versus 6.5 hours... so no, it would not be worth it.
I think what you're calling scalloping is sailing a close-hauled course and heading up as the wind strength increases to take advantage of the change in apparent wind and then falling off a bit as it weakens, to prevent stalling the boat. This practice generally yields the best boat speed but leaves a "scalloped" track, if viewed from above. AFAIK
, it doesn't make much sense to do this if not sailing close hauled, since you can easily trim the sails to have the same effect... Sailing close-hauled, the sails are trimmed in for maximum effect and can not be trimmed to adjust for the increase in wind, so the boat's course is adjusted to take advantage instead.