In the upcoming expansion I heard that we will get an increased cap of devotion from 50 to a still undecided number. My question is, does restoring shrines past the current 50 limit “stores” the actual value or is it “wasted” and I will permanently lose a source of devotion points when the expansion does come out? Basically, should I restore shrines if I already hit the 50 cap?
XP and loot is a minor concern compared to missing an easy source of of dev points imo. Though I’m guessing in the upcoming expansion there will also be more new shrines than how much the cap is raised so I wouldn’t miss out anything in the end. Still, I’d like some confirmation on this matter.
Pretty much this.
There will definitely be more than enough new shrines, so you do not need to “save” current shrines for later. I think Zantai has posted this some time ago, but I am far to lazy to look for the post atm. 
Currently there are 59 shrines which means you can “save” 9 shrines (which is what I do) to gain the devotions points rather easy when the expansion goes live.
and you can save up those shrines from the expansion to get XP/Loot to level up faster.
what most people do is; cleansing all the shrines all 59, but I don’t see the point in that because you will only get some loot (maybe some XP when you aren’t lvl 85) saving them so you can restore them during the expansion seems much better imo or getting the devotion points in Crucible
What I though was we get up to 60 devotion points so + 10 to invest in constellations and 14 new constellation in the devotion system itself with the expansion