Done right, it avoids bugs - especially complex hard-to-roll-back state-related bugs - that can arise from discrete waterfall-style releases of big and complex features all at once.
Your comment seems to be making a hell of a lot of assumptions and associations which seem very specific to the environment you work in[0], but stated as though you think the entire world must be working in the same way. It feels a bit like a child insisting that they don't speak with an accent.
[0] "One deploy is one feature", "every company has 'BA's and 'PM's" [we had the latter but I'm scare-quoting both because they are far from universal], "each feature has to be 'identified' by said BA or PM", etc. Also, this seems to be written not only from a staid perspective but from a small-co perspective; for large companies, even 3000 features is not a huge number, and wouldn't be more than maybe 5 or 10 per team.