It is worth it if you like short serialized stories and expect to finish a couple of standard series each month, which is roughly what Premium's monthly tokens pay for. If you only want one series, buying tokens for it is cheaper. Watch the two free episodes first and decide on the story, not the trailer.
The maths
A standard five-episode series costs 36 tokens after its free part; a headliner series costs 90. Premium's 100 tokens a month covers two standard series, or one headliner series, plus unlimited chat.
Who will be disappointed
Anyone expecting long episodes or a free full catalogue. Chapters are short by design and the free part ends early.
More answers are on the backstage page.