Bright Engrams are important if you want to get shaders in Destiny 2. They drop a lot of shaders which are now one time consumables so they will end up disappearing once you use them. This might have led to a little controversy among fans but the game director has backed up this decision saying it was necessary for the game.
There is one aspect of the Bright Engrams that hasn’t really been put to spotlight and it is the earning rate for them. According to a thread on reddit, the earning rate seems to increase as you level up your character. This means you will need to earn more experience each time to get more of the Bright Engrams. It starts moderately at 40k experience for the first bright engram and can go all the way to 80k as you reach the level cap.
This shouldn’t be an issue except the problem here is that Destiny 2 also offers microtransactions so you will be able to buy these bright engrams using real-life money. If the drop rate for these engrams is higher in the start and then gradually slows down, you might be inclined to either grind even more, or just spend money to get them. There is no confirmed level cap available for these engrams so the only thing to know is that their requirements steadily increase after level up and their earning rate decreases along with it.
Hopefully Bungie can clarify more of this mechanic in detail but as of right now, fans of the game are finding it difficult to justify this restriction applied for the engrams in light of the microtransactions available in the game.