The phrase "great sweet spots" is an idiomatic expression that means a place or situation where everything works out perfectly, and there are no problems or difficulties. Full definition
That's too bad, because it hits a really great sweet spot. (newatlas.com)
Flying Blue has a number of great sweet spots in economy class but unfortunately isn't the most lucrative reward program for business class flights because many of these flights are on the higher side of redemptions and many redemptions also come with high fees. (uponarriving.com)
Other great sweet spots are for routes to South America, Australia, and certain intra-continental flights. (uponarriving.com)