for real! some later versions of the X1C have had S3 patched in but when the X1C6 was first released this was a surprise to me. Apparently Windows is moving towards S1-only and that gets reflected in firmwares originally designed for windows computers.
For the uninitiated, without S3 closing the laptop lid will either continue to drain battery pretty damned quickly (S1) OR cause the OS to take much longer to resume completely from disk (S4 aka hibernate). As SSDs get bigger/faster/cheaper in comparison to RAM, S4 will start to seem more equivalent, but to make this sensible on an ultrabook you might want to opt for that 1+TB NVME so you can hibernate on lid-shut without eating a significant fraction of your disk on swap.
For the uninitiated, without S3 closing the laptop lid will either continue to drain battery pretty damned quickly (S1) OR cause the OS to take much longer to resume completely from disk (S4 aka hibernate). As SSDs get bigger/faster/cheaper in comparison to RAM, S4 will start to seem more equivalent, but to make this sensible on an ultrabook you might want to opt for that 1+TB NVME so you can hibernate on lid-shut without eating a significant fraction of your disk on swap.