Restricting Mastery tokens by map is still a weirdly blatant example of Riot promoting Summoner's Rift at the expense of League's other game modes. What should just be a neat little bonus feature for League of Legends players has been twisted into an exclusive feature for SR players. The official reasoning of "high competitive standards" completely falls apart with Normal SR having tokens, but not Ranked Twisted Treeline. So Ranked TT is competitive enough for players to earn ranked rewards, including limited-edition physical merchandise, but not competitive enough for Mastery tokens. Meanwhile, Normal SR is competitive enough for tokens, but not ranked rewards.
If Riot wants to stick with the "competitive standard" explanation, then Mastery tokens should only be available in Ranked queues (and possibly Clash). On the other hand, if tokens remain available in Normal SR, then tokens should just be available everywhere. The current situation of half-casual and half-competitive is simply ridiculous.