Why would I? Half of my room is covered by SW things. But it's a bit different thing. High-end technology saber is not the same like metal sword in a futuristic word. You gonna jump out with things like vibroblade from SW. Sure, it's a metal sword but only idiot would spent time and resources to equip army with vibroblades vs laser guns. It would be like running with a slingshot vs dug down machine guns.
Still, you won't find anyone using vibroblade vs guns.
That's actually exactly the same in in WH40k. The swords and axes you see aren't simple metal swords but either Power Swords/Axes or Chainswords/axes, or my personal favorite, Lightning Claws. Their super hightech swords with Power weapons being designed to cut through heavy armor like a knife through butter and with Chain weapons designed to brutalize the enemy. They are vibroblade equivalents.
Typically, melee combatants equipped with these weapons normally have a way to close the distance between them and their targets quickly or wear extremely heavy armor, or both. Assault Marines normally are equipped with Chainswords and a Bolter Pistol along with Space Marine armor and jump packs, they can easily close the distance between them and their target and cut them to shreds. The even heavier version of Assault Marines, Assault Terminator Marines, are equipped with harder hitting Thunderhammers and Shields, the even stronger Terminator armor, and teleporter packs.
We're talking about multi-ton monstrousities just landing into the middle densely packed laser gun formations wrecking havoc because of their superior melee weapons and armor. Your regular rank-and-file human, the typical Guardsman, would never dream of doing that. He'll hid behind a nice piece of cover taking potshots with his lasgun and hope the Commissar doesn't decide to make an example of him.