Sorry, I was using the term similarly to "If you want to do Ultimate, you are obliged to be well-geared and choose a job that isn't distinctly sub-optimal", but in this case "If one wants to grind tomes efficiently, roulettes are obligatory."
They are not
strictly necessary (you can get carried even in Ultimate), but you'd certainly never be able to complain about your inability to achieve those ends if you didn't first use those means.
Looking at roulettes specifically, we are systematically encouraged to spend less time on content of our choosing as to benefit the content of others. It largely cycles back to where we all at many point have benefited from roulettes (even if we do still get the conspicuous party of all 80s doing Titan for a Trial roulette), backing it balance back while also giving us some variety.
If that were the end of it, I wouldn't see even the slightest issue. But...
- What about the people who want to random content and/or content that helps people (for them, that "random" is then still "chosen" content, in a sense)?
- And, what does the massive disparity in EXP efficiency between just doing dailies and actually progressing through content at your level do for your sense of progression when leveling a job?
Or, more simply put, why don't Roulettes just attempt to make other content just slightly more efficient than your own on your first use per day and only slightly less efficient thereafter, instead of initially far more efficient and then nearly worthless?
Would that added flexibility, by less noticeably conditioning the player or skewing their decision with the relative carrot (efficiency for doing what roulettes ask of you) and stick (inefficiency for doing what you want), be better or worse for the game?