Trial reads I believe probably are good in short term but potentially bad in long term.
I guess rationale is that you make more money releasing 10 chapters for 10 novels than you do releasing 100 chapters for 1 novel. Then if you want to go to the extreme you can then take these 10 novels and drop the 7 worst performing ones to increase revenue per chapter. Then if you get it so that let's say if every 100 chapters if it's not in the top 50 percentile it also gets dropped to eliminate the less profitable novels it also increases revenue per chapter.
It all sounds very good but it's hard to say if trial novels get additional income or simply divert existing income. Other problem is that while all these calculations talk about return on investment for Webnovel or Translator there isn't any return on investment for the reader. If readers pay for privilege and then find their novels dropped then it's a poor return on investment for the reader and is likely to discourage future spending.
Interestingly if a novel has to stay in the top 50 percentile and it's reviewed every 100 chapters then an "average" novel has a 99.9% chance of being dropped within 1000 chapters (0.510 is 0.097% chance of not being dropped).
If looking for the optimal approach for return on investment I would suggest only translating around 20 novels that makes up around half of Webnovel's income and commit to finishing them and licence the rest to other TLs/sites. Once one is finished a new novel can be picked up. Problem is Webnovel has tried to monopolise the market and overextended leading to loads of dead novels and it's not benefited Webnovel, translators or the readers as having series migrated to Webnovel to be subsequently dropped is a loss to everyone.