I used a laptop for in a bartop build. The specs were a little better, but not a huge amount. It was a really old core 2 duo running around 1.8 GHz I think. Running a mame version in the 140 or 150 range but sticking to older roms. Mostly vertical games from before 85 or so.
One thing that was a bit of a pain was powering the laptop on and off. I ended up soldering a couple of wires from an old IDE ribbon to the laptops power switch, then ran those to an arcade button. That involved taking all sorts of panels off the laptop to get the power switch loose to a point where I could even see the solder pads, which were also really small. Also you might have issues with secondary monitors, resolutions, and the good old lid switch. One thing you might have to do is fully remove the laptop screen to solve these issues. Some laptops will work just fine when the laptop is closed based on the windows power options being set. Mine would not power up with the lid closed though despite my soldered on power leads.
Food for thought man. Its certainly possible, just be prepared to do some additional work to get it all the way.