There are pros and cons to this, obviously
The set of keywords here means Danitha's not too bad of a target for those modifications, but this is still in support territory
2 Add: Ureni, The Song Unending Cut: Spit Flame Yes, the deck already has Ureni as the head of the deck but getting a second, more powerful one in the 99 is always a good option
Just think, those ridiculously priced Evolving Skies booster boxes on TCG Player were a dime a dozen at one point
The biggest takeaway is that all the cards in any given rarity level all have approximately the same pull rate
However, there are better options like Thieves' Guild Enforcer or Dark Confidant that offer more consistent value and impact on the board, making Gollum a less optimal choice for competitive play