Can this tool be used to open cans?
Those two versions of a can opener operate on exactly the same principle. The difference is that the simpler one has a cutting "blade" that's basically just a part of the main body that's been bent at right angles and maybe sharpened a little bit, while the nicer one has an actual separate circular blade.1 Both will serve the purpose of opening cans, but the simpler one will probably need more physical effort expended.

1I think - it's actually hard to tell, given that the picture is from the least useful angle imaginable.