1. I often see people stating that they want to see the level so they can recruit easier while in global.
2. While I highly doubt people are really recruiting THAT much, I can still prove that league shields can, to a very good extent, tell a recruiter how good somebody is.
3. Here's how:
YOU KNOW DARN WELL THAT IF YOU SEE EITHER ONE OF THESE:
...next to their name (number or no number), that they are WORTH RECRUITING.
Not true, there are premmie TH6s in masters.
4. If they have a crystal shield, like me, then they fall into that grey area, semi-serious, or making a trophy rush.
What if you are farming in crystal, and you legitimately farmed everything and almost maxed? Is that semi serious?
5. If they have a bronze, silver, or gold, they are either a noob, farming, or still trying to find the best defense/offense to move up a league. Basically, your average player.
Same as above. There could be above average players in gold league.
So, there you have it. You don't need the lvl to give you a relative idea of what kind of player you have that may or may not be worth being a member of your clan.
XP Level and troop levels are the best way to recruit people.