^That pretty much was my doctrine until recently, too.
However, I've found empirically that enemy monks are either dead or out of range in so many situations (with allied Rook, TB, Occ, QoT, to name a few prominent cases), while you, as Sedna, will naturally outheal enemy generals by a huge margin anyway. Since you are not a farming powerhouse by any means (fastish dynamic Sed I play now is having a much easier time in this respect than a pure support static Sed, but still...), every level counts. Basically, you don't have any points to spare until level 15 or so, and I just don't think CH is ultimately worth it, unless it's a counter to another Sed with CH,
Also, in my opinion, monks' healing is only realistically useful over long periods of time, while laning semi-passively. I've seen it change the outcome of an occasional early-game skirmish, but that happens only very early and, indeed, very occasionally.