My verdict: the hub for centralizing all your customer data.
Segment simplifies managing your data stack, but it's overkill for small teams. The CDP (Customer Data Platform) for centralizing all your customer data. Segment collects data from your site/app and sends it to all your tools (analytics, CRM, email, etc.) via a single integration. You integrate Segment once, and you can add/remove tools without touching the code. Free up to 1000 visitors/month, then it goes up fast. If you have a complex data stack, Segment is a game-changer. Otherwise, it's overkill.
What I like less: pricing that explodes when you scale. And the fact that for a simple stack with 2-3 tools, it's over-engineering.
My advice: Segment only makes sense if you have 5+ tools that need the same user data. For an early-stage startup with GA + Mixpanel + a CRM, you can do without it. When your data stack becomes complex, Segment simplifies everything.