Launching a game means that the entire Steam Window fades and it will become entirely unusable until the game starts. That is not a separate startup window, thats just an embedded element inside the main one. If you accidentally click outside, the game startup gets canceled.
It is a bit more than mildly frustrating when Im waiting on the Vulkan shaders for BFV for like half an hour to process.
an “SSD” can be either a SATA-cable connected 2.5" SSD, a M.2 SATA (protocol) SSD, or an M.2 PCIe SSD. their respective maximum R/W speed increases significantly in this order, so M.2 is not the only way to connect an SSD, at least not as long as cable-sata SSDs still exist.