Blog Post
In addition to all the points being made about how Pipelines are not yet stable enough to be relied on, even if they were, i do not think they can replace webhooks. They are two separate tools.
Webhooks are like database triggers, living at the data layer, watching for changes and immediately firing and making related data updates. Very useful for things like logging changes to certain fields, or triggering a change on a parent record when a child is updated.
Pipelines are an external layer of application logic, more powerful but more complicated great for when you need multi-step actions or integrations with external apps.
Certain things belong at the database layer and certain things belong in the application layer, removing access to one just because the other can technically do it is still a step backwards.