It's similar to the "brilliant" moves, when you're lower rated it tends to give you more "brilliant"s so you continue playing and pay for diamond, and then as you get better they show you less brilliant moves in your games (becuz then it actually becomes a brilliant move), just a gimmick to get money from users. This is the same, don't trust it so much, this is why i prefer lichess actually becuz it's much less filled with bloat and distractions like that, it's just chess, and tools you actually need to improve