If you want to play any normal AAA game (excluding indie pixel software rendered things - but sometimes even those), the difference in power consumption is not even a challenging comparison - a desktop CPU alone pulls more wattage than the deck under maximum load (2-4x deck), before we even get into GPU power usage (usually 10x the max usage of the deck). If you are looking to save on that power bill - a mobile system that has to worry about batteries will always save energy that a desktop won’t.
If you want to play any normal AAA game (excluding indie pixel software rendered things - but sometimes even those), the difference in power consumption is not even a challenging comparison - a desktop CPU alone pulls more wattage than the deck under maximum load (2-4x deck), before we even get into GPU power usage (usually 10x the max usage of the deck). If you are looking to save on that power bill - a mobile system that has to worry about batteries will always save energy that a desktop won’t.