I myself use wireless for most of the computers in my house and I have many reasons to do so. I have my server hard-wired, but just about everything else is wireless.
First of all, my house was built in the 1950s so the walls are plaster and 1" thick. It's nearly impossible to get behind them without completely destroying the walls.
Second, on any reasonably large sized house, it is much more economical to go with wireless. We have a few laptops that are all wireless, and it kind of defeats their purpose to have to plug them in to get internet. Also, we have computers in just about every room of the house and we would have to buy hundreds of feet of cable in order to wire them. You can find decent wireless receivers for around $20 which is far less than we'd spend on the cabling to reach some of the far away rooms. And of course, we have the aforementioned problem of the thick walls we'd have to deal with.
Third, I don't know about you, but most of what I do at home is browse the internet doing nothing in particular, play games, and watch media off of my server. Security isn't my highest priority, I could care less if someone is able to intercept my transmission and see that I'm viewing the latest and stupidest video on Youtube. Not exactly something I'd need to keep intensely secure. If I had a top secret clearance and worked on important documents in my house, maybe that'd be a bit different. Anything secure I do at work during the day where my line is hard-wired.
Fourth, you mentioned lower speed. My wireless router is an 802.11G router, with theoretical speeds of 55 Mbps but in reality achieves around 15-20 Mbps. The uplink DSL to my house is a paltry 3Mbps. What point is there to do all this work to upgrade my internal network to 100 or 1000 Mbit when my total throughput to the outside world is capped at much lower? Unless I was doing a lot of transferring large files around inside my network which I seldom do, it seems like a lot of pointless work.
Last, there is of course a bit of the "lazy-factor," but it doesn't drive my decision, the other factors mentioned above do. But it is incredibly nice to know that I don't have to try and retrofit an entire house with new cables, redoing the walls where I try to snake the cable through, repainting them after I mess them up, buying cable and jacks and ends and spending hours and hours and hours trying to snake the cable throughout my entire house. You could call me another lazy American, but with the above reasons, I'd call running cables through my house creating a mess and a headache that aren't merited and have very little benefit.