Why do people like FOW/UW so much?

Might sound like a strange question, but I just went into FOW with a party for the first time, and Im just wondering why people like it so much.

FOW-It drops Shards, I luckly got 3. But besides that, i didnt get very good loot. Most werent even Max Dmg weapons, Only got 2 gold(chests) and like 2 purples from Drops. also get no Greens, but its good XP.

UW- Never gone here yet, but want to soon. There also isent greens, and you have to be in favor, same with FOW.

Tombs-Also dont know, but it has greens,sounds like it has good loot, and can go in when ever you want.

SF-Only been in once, I was tank and our party was bad. We fought like 2 groups and people started to leave, mOnks first. But also, They have greens and can go in when ever, no need for Favor.

Im still only a noob, only been playing for 1 month, got 2 lv 20s but still learning all the high lv stuff. But it seems like thoes are the best high lv group areas. But why are the two favor areas(FOW/UW) so popular? is it for the challage? I mean, it was fun and all. But if people are looking at drop/loot wise, wouldent SF/Tombs be better?

Please correct me if Im wrong, just wondering.

Thanks alot

people love uw for exp, ecto drops, and chest drops
people love fow for exp, shard drops, chest drops, and FOW armor you have to go there to go pick it up

Fow and UW are loved so much because
1) Fow is the only place that drops shards and UW is the only place that drop ectos (Tombs drop them also now, but much less often)
2) Fow is the only place that drop Chaos Axe, Shadow blade, Shadow shield, Shadow bow, and Shadow staff. A perfect Chaos axe (I.e. req 8 15>50) can sell for up to 800k and A truly perfect shadow shield (I.e. +30 -5/20%) can go upward to millions
3) UW is the only place that drop Eternal bow, Eternal shield, Storm bows, and ghostly staff. Once again, a perfect Storm bow will go for around 500k, not as much as chaos axe. And a perfect Eternal shield will also go in to the millions.
4) Finally, Fow is where you can craft fissure armor.

All require fast thinking and decent players and grouping. It brings people who are good at the game around the same area.

For people who have beaten the game, if you have to be playing in a group anywhere, it might as well be where you get the most exp, have a higher probabily of getting items worth something, and getting items you can get no where else.

I guess it just simple economics, if you are investing your time in playing, you get the best return from UW and FoW

Also Crystalline Swords drop in FoW for sure, although the drop rate is extremely low. A decent Crystalline can sell for a few hundred k.

And gold > greens.

I love fow very much becasue it gives me at least 2 skill points per run that allows me to unlock more skills in faction. I am not looking for a good loot in fow becasue I can have better income from elsewhere.