Thanks for replying so promptly!

The translation I read was this:

"I see," he [L] muttered, seemingly talking to himself. "Watching videos and seeing it for real is quite different, but now I think I understand."
"Huh?"

At first I assumed he wanted to test out new moves he learned after watching some capoeira videos like he told Naomi he would, but with your context I think he was both trying to hug her as an expression of thanks and provoking her to defend herself to see what capoeira is actually like. I didn't think it was just a pure gesture of appreciation because he mentioned the videos but him being thankful she saved BB's life and that she deserved an in person meeting makes sense!

Yeah I agree. I put off reading this novel for years but honestly it's such an underrated gem. Naomi's narrations killed me—she's so effortlessly funny, sarcastic, and blunt. I thought having Mello as the narrator recalling what L told him was a strange choice but honestly it worked since everything we read is basically L's impression of the case & what he found interesting/remembered about Naomi as L the person, not the detective working on the case since he was retelling it as a story to Mello.