Just going against the trend here, I'll refer to Phantasy Star Online. After maxing a character or two, myself and a fair few others got into self-imposed permadeath playing and I have to say it was by far the most compelling play that game provided. It was like crack for all of us. More to the point, the game's economy was actually more suited to this type of play, as if they had distributed items and rewards based on the idea that players would be playing one adventure, not a repeat cycle of them. And not just distribution; many cheap special weapons that had always been rubbish from the start, that had always come across as useless filler in the game, suddenly found themselves filling previously pointless roles so well that it really looked like this was how the game was deliberately designed. Except, it apparently wasn't. PSO has never had a permadeath mode.
So in one aspect the actual play was quite simply better (in our opinions) due to the added tension, and in another aspect the economy was much, much more rewarding due to the increased difficulty of access to the good loot and the increased room in gameplay for the lower special weapons.
I don't know what can be learnt from that. The gameplay factor was only successful because of the online component. Playing alone would have become too frustrating to carry a full game. On that note, Realm of the Mad God (check on Steam, it's free) is an online MMO-shootey-RPG that uses permadeath and only permadeath. The economy factor of PSO was definitely improved by permadeath play however.
The pseudo-update, PSO ver.2, changed a particular mechanic in combat and that unfortunately made permadeath no longer viable.