Hello, I'd say it's relevant.
For those of you who don't know what the OP is talking about. It's just CSS tables (display:table and its children)...it's almost to the point where it can be done throughout every browser. The only problem is that IE7 is still somewhat alive. You'd have to check with your website statistics and see how many users are using IE7. Display:table works right now, everywhere, except IE7 (and IE6 if you even want to go back that far, but that's dead and you shouldn't bother supporting)
I'd say display:table is nice, and even ignoring IE7, it's a good layout tool. Now, note that I've never been in the era of using HTML tables, I jumped straight into CSS (Kevin in the video seems to make CSS seem much harder than it was. I never really struggled or "wrestled" with CSS.) I'd still stick to floating for layouts except for the exceptions where I truly believe CSS tables are the better option. That's ignoring IE7 though. I wouldn't feel comfortable using them quite yet knowing IE7 is still alive. Your call though. It's your website :).