Yes, they work perfectly. "Platinum" (or "Greatest Hits" / "Essentials") is a sales milestone label, not a separate format. The confusion stems from the PSP Go (digital-only) versus regular PSP models (UMD).
| PSP Model | UMD Games (Platinum/GH) | PSN Digital Games |
|---|---|---|
| PSP-1000/2000/3000/E1000 | ✅ Yes | ✅ Yes (via PSN / CFW) |
| PSP Go | ❌ No UMD drive | ✅ Yes (native) |
Bottom Line: A "Platinum" UMD game works perfectly on a regular PSP. The only incompatibility is physical UMDs on PSP Go.