Why is bags under his eyes Ryou accepted as canon?

It is purely fanon. I mean, do not get me wrong, I LOVE the headcanon and idea of it but it is strange to me even so.

I guess one could blame his wonky sleep schedule- in which case blame the spirit of the Ring, but yeah.

Know who else should totally have bags under his eyes in canon but doesn’t? 
Seto Kaiba.

The guy is up damn near 24/7 and always working on something in between pining after defeating Yugi (Yami). He just must some great makeup to hide it all to keep looking professional.

Know who has bags under his eyes in canon though?

Project MI (YGO implied Axisshipping and Dangershipping)

Project MI had once felt self explanatory. It was surely just to throw off anyone prying by the simplicities of the naming alone as well as be a subtle reprise to ‘me’. A nod from Seto Kaiba to himself for coming up with something so revolutionary. A self made pat on the back.
A scoff escaped him as Siegfried closed the tab only for the screen to become void with black and a small red tab at the bottom to reveal. His own reflection on the darkened device warning him of the frown that had carved itself upon his normally flawless face. Such an ugly look even by his own standards but as he leaned back he could see the covered form on the table just beyond.
“Project MI,” Siegfried spoke placidly only to look back at his screen. The scowl now more a cruel smile. Frightening but beautiful again in appearance. “Marik Ishtar, Herr Kaiba says. Tsk,” he opened the tab and opened a folder containing several stolen video recording that Kaiba had once buried deep in humiliation for losing his own tournament.
There on the screen now stood a nightmare of a man. Tall, darkened skin, with lightning for hair, and an attitude almost as proud as the chic Seto Kaiba.
But that man had died. There were articles on it. The same tournament in fact. A secondary reason upon many to quickly announce the winner then bury all unsavory details with curt responses.
The real burning question was still lingering in Siegfried’s frazzled mind. Why would Kaiba make a synthetic of the late Marik Ishtar and not of himself? Was it mere vanity and thinking of ‘there can only be one’ or was he-?
A disgusted scoff left the pink haired CEO.
“Did you love him?” he asked to his imagined Seto that remained quiet. “Enough to create this sorry excuse for a person?” He asked louder now gesturing off to the still mound hidden by a white sheet. “This is just a machine! Nothing more than metal!” he snarled. His tension still lingering but his voice that crackled with animosity dropped into a more soft spoken rage. “Wire, cooling fluid, pipes… all so cleverly adorned with synthetic flesh. Nothing about this /thing/ is real.”
No one answered. Teetched now clenched together, Siegfried paused the video on a closeup of Ishtar’s face. Pearly white teeth showing in a roguishly handsome smile even by his own tastes. It was easy to see how Seto Kaiba had fallen for the fiend but to go as low as to build a replica of the dead? Now that was truly pathetic.
Well, this depressive love of Kaiba’s needed to be laid to rest. Unfortunately the only way for that to go into motion was left up to him. A horrendous task but one Siegfried was willing to get on and over with in order to save his friend. A truly selfless reason assuredly.
“You’ll thank me for this.” Again no one answered. Siegfried now up from his seat and forsaking his computer to tear off the sheet now revealing the nude form of Project MI. “After all… this is for your own good.”

Based on an RP my gf and I been doing. 
Sadly my ability to focus crapped out before I got to the part I really wanted.
The delicious forced mind reset and override Siegfried performs on the still fully conscious Marik who has just come to terms with trying to be a good person~ Oh to have all that progress just stripped away in such a painful manner! After all, there is only so much a soul can take before it becomes too damaged to heal.

Random Seto Kaiba thought

So like all greats when they die the media attempts to smear their name as they can not defend themselves.
So… What if they went to do that for Seto but Mokuba managed to intervene and rise up to stop it? Putting out the word of all of his big brother’s good qualities? All the anonymous donations no longer anonymous to orphanages and youth survivors of domestic abuse, funding into the art programs in schools, and various other things?
Sure, Kaiba was a jerk in his life but life made him need to be that way to survive it and now that he is gone Mokuba is going to make everyone realize that Seto only acted like a jerk but hidden away from public view was a man with a heart of gold he knew too many people would want to sell away.