1. From the articles I tried, the summaries seem to be very basic. They don't seem to capture the essential points of the articles it is trying to summarize.
2. I tried the 'advanced summarizer' too. Here again, it seems to have the same problem. Worse, it seems to skip parts of the article, especially if they are beyond a certain length.
3. The landing page is nice. But the product seems to be targeted towards people who want to share a summary of a random blog post rather than try and save time reading the article.
In my opinion, SMMRY, as mentioned in another comment and which I've used since whenever, seems like a much better product. Additionally, SMMRY also gives you the capability of expanding the number of lines of the summary in case you've found the article interesting and want to read a few more details of it, rather than the full thing.
SMMRY: https://smmry.com/