I could imagine that this could mask bugs actually. Recently a project I work on started deadlocking. This meant randomly a single request thread would spin endlessly.

Now imagine we had a magic "start more servers" mode. We push new builds once a month, say. We'd just keep spinning up servers automatically without anyone noticing probably. Soon we'd hit some other system bottleneck (I'd bet something like too much DB traffic), and then we'd be off on a wild goose chase wondering what was wrong with the database or something.

(These are semi-hypothetical. As a team we discussed whether we wanted to have our monitoring processes spin up new frontends and decided that we should probably keep humans in the loop ;))