Google is disabling the Request Indexing feature of the URL Inspection Tool temporarily within the Search Console.
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We have disabled the "Request Indexing" feature of the URL Inspection Tool, in order to make some infrastructure changes. We expect it will return in the coming weeks. We continue to find & index content through our regular methods, as covered here: https://t.co/rMFVaLht6V
— Google Search Central (@googlesearchc) October 14, 2020
The Request Indexing feature can be used to request a crawl of individual URLs. This feature is usually used when the website owners publish a new webpage or make any modifications to an existing page. It increases the process of Google adding the new content to the search index without any guarantee. The feature does not really promise instant indexing as in some cases Google may not want to index the content at all.
Statement In Search Console Help Page
Requesting a crawl does not guarantee that inclusion will happen instantly or even at all. Our systems prioritize the fast inclusion of high quality, useful content.
Conclusion
Considering all this it can be said that the Request Indexing is some sort of feature SEOs and the website owners can manage to temporarily live without. That’s especially true if Google’s infrastructure changes lead to some improvements. And it is not like the new content will not be indexed in the meantime. According to what Google said in a tweet, it will keep on finding and indexing content via its regular methods.