In many contexts you are correct & further, as someone in that earlier thread about the AWS us-east-1 outage mentioned, customers can be more forgiving of outages if you as the vendor can point to a widespread AWS us-east-1 outage and note that us-east-1 is down for everyone.

But, as JSR_FDED's sibling comment notes & as is spelled out in the article, authress' business model offering an auth service means that their outage may entirely brick their clients customer facing auth / machine to machine auth.

I've worked in megacorp environments where an outage of certain internal services responsible for auth or issuing JWTs would break tens or hundreds of internal services and break various customer-facing flows. In many business contexts a big messy customer facing outage for a day or so doesn't actually matter but in some contexts it really can. In terms of blast radius, unavailability of a key auth service depended on by hundreds of things is up there with, i dunno, breaking the network.