Mana and life BOCL don't get boosted by Bo

ISO your source to confirm that. Even if this is true though, it's still an extremely viable item.

At level 94, you're getting +70 mana. That's the equivalent of 35 stat points into Energy. This is the base diadem, not including your jewel options.
With jewels you can easily push an additional +60 or more to mana. It heavily competes, if not exceeds, the value you'd get out of 2/30/20/STATS/2 diadems.

Stat points into energy get boosted by BO so no it isn't the equivalent. Check it in game yourself with this helm or a BK ring

Hes not lying CuHz the Gzzzzz dunnoxd know wtf he talking about and thats on grape CuHz