It varies, each shrine has its own minimum level, and offers its own reward. Also, all of them give exp.
So far:
Lvl 20 - Fists of Enlightenment (Fist weapon)
Lvl 30 - Mystic Repulse (Spell like exori hur, but way stronger, 14 sec cooldown) and 10% boost in auto attacks (20% when serene)
Lvl 40 - Legs on Enlightenment and 10% boost in auto attacks (20% when serene)
Lvl 50 - Nunchaku of Enlightenment and 10% boost in auto attacks (20% when serene)
Lvl 70 - Coned Hat of Enlightenment and 10% boost in auto attacks (20% when serene)
Lvl 100 - Sais of Enlightenment and 10% boost in auto attacks (20% when serene)
Lvl 110 - Forceful Uppercut Spell (Same as Exori Gran Ico, 40 sec cooldown, builder kind - Gives you harmony point)
Lvl 150 - Robe of Enlightenment
Lvl 275 - Next week only, unless someone rushes 125 levels tomorrow (Feb 26th)
So basically yes, it does have great impact in gameplay. Auto attacks become amazing after having shrines.