Ascendant energy is worth much more once you have your main to lvl 30. i have a lvl 30 hunter and a lvl 29 titan and i have more shard than you could ever even use, but i have very minimal energy. its nice to have a lot of weapons upgraded fully for when there is different burns in nightfall, and just different mission in general(enemy shields). raid is the best place to get shards and energy but its still random. this past week i got about 30 shards or so and maybe 10-12 energy, and i dont need shards at all i prob have around 150-200. anyway all im saying is there will come a point when u hit max lvl and you wish u had energy and not shards.