What are DePIN projects?

I am completely stuck: What are DePIN projects?

Hey everyone, I'm losing my absolute mind trying to figure out exactly what are DePIN projects?

Seriously. I've spent three consecutive nights falling down a massive, brain-melting Web3 rabbit hole. I am still head-scratching.

A couple of years back, I dropped cash on a Bobcat miner for the Helium network. I plugged that little plastic box in by my living room window—hoping for magic internet money—and it actually worked for a bit. Back then, we just called it decentralized IoT. Fast forward to this week. Now every single crypto forum is hyper-fixated on this shiny new acronym.

So, I have to ask the veterans here: what are DePIN projects, really?

Is this just a slick, recycled marketing gimmick for the exact same hardware-based tokenomics we played with in 2021? Or did I miss a massive foundational shift in how these physical networks operate? When I try reading the current whitepapers, my eyes immediately glaze over.

My exact friction points

Here is where I get trapped:

• Categorization: Do server-sharing protocols (like Filecoin or Render) actually count?
• The Hardware Sunk Cost: Are we always forced to buy super proprietary routers and sensors?
• Actual Utility: Who is genuinely buying this real-world sensor data?

I tried mapping out my confusion visually.

I really need practical examples. If your non-crypto buddy at a bar asks you, "hey man, what are DePIN projects?", how do you break it down without sounding like a crazy person? I genuinely want to allocate some portfolio space here (and maybe run a node), but I absolutely refuse to buy into something I fundamentally cannot grasp.

Help me out.