In Clash Royal, it's mostly clear that when you're in a clan and you are not yet King 13 you should give cards to other teammates. You'll get XP points plus gold.
But what if you're King 13 and you only get gold and star points? Those are used to get clothes for your troops. If you totally don't mind about having such clothes, is it still worth giving cards only for gold?
Best Answer
New cards come out time-to-time and require gold to upgrade, so donating cards for gold could be worth it for upgrading new cards quicker as they are released (meaning, you'd just have to wait for getting enough cards instead of cards AND gold, since higher upgrades could get costly).
If you are already sitting on a huge pile of gold (from either stockpiling or maybe you spend enough real money on the game to accumulate) then the only other thing would be to show support for clan mates (and maybe they could be more willing to trade those future new cards to you if you request them, if they care enough to remember).
But if you have plenty of gold for future card releases, don't care about star points for cosmetic upgrades, and don't mind potentially being seen as a free loader from your clan mates (no judgement here)... then there is no real advantage to donating cards once you reach King level 13.