Solidstate is the only way to go for online storage. The speed difference with any nVME is so much compared to even a SATA SSD it would be silly not to at least have the boot drive and game install storage using it. But even an SATA SSD can breath new life into old hardware, such as a laptop not really being used for gaming.

But for offline storage mechanical drives do still offer the capacity far cheaper then solidstate can offer. 4TB nVMEs are still too expensive, although I've read they should soon be dropping in price. But 2TB ones are now at a great price, even Gen4. Which is an acceptible size for OS and software installs.