The “shield” on the SSDs is a heatsink which is why it’s metal and has the “spikes” which increase surface area for dissipating heat. Some NVMe drives need a heatsink, some don’t, so it’s better to keep them cool. The tower + fan is the CPU cooler that uses conduction + convection to pull heat from the CPU. This workstation has an Intel Xeon which can get hot enough that it needs good cooling to avoid thermal throttling and/or getting damaged from overheating. IMO every software developer should build a PC at some point. Understanding basic computer hardware can be very useful for saving time with troubleshooting if/when something goes wrong and it’s also a great way to save money.