No they arent'. Motes of light and legendary marks were both materials that are/were generated to the player as the result of NORMAL game play. Also both materials were freely farmable. So the more you played, the more you earned. Cores are an artifiically created "grind" that serves no purpose but to extend play without acutally rewarding the player. They dont' drop from normal play. They either have to be bought.....earned by grinding some of the most tedious parts of the game...... ...and they are effectively capped. Either directly (Spider bounties).....with brutal feedback mechanics designed to deplete you resources (buying them from Spider).....or hiding them behind multiple layers of randomness (Scrapper bounties, Matterweave, dismantling Level 4 or higher gear). The difference is that the former is a tranparent investment process. The other is set up to act like a game of chance, where the player wagers their time and effort, and then has to HOPE the game spits out something that will actually progress their character. This is mobile game-level shit.