Sure, she was. But to say Smash didn't hugely benefit her popularity is just wrong. She's not just a waifu, but it's also undeniable to say that much of her popularity came from being one; really, what about her character would make her so popular? She's really just a generic time traveler, seeing as her personality is pretty dry, and she (Lucina, not "Marth") doesn't really have plot importance. And Chrom barely got any Smash memes, really just the fact that he didn't get in; the average Smash player won't care about him like they do Ike, Marth, Lucina, or Robin.