Any of these games are dependant on luck, YGO abused the 'heart of the cards' thing which clearly allowed for some really lucky draws. The point is, however, at the times YGO would use a device like this, some big strategy was already being put to work by the player, and he'd usually be missing one card to complete it. It worked because no matter how cheesy it might have been, it made for exciting climaxes and all.
Vanguad's luck, on the other hand, works the same way towards basically any attacking monster. Attack something and hope for a drive trigger. There's hardly any strategy here, it's simply a free power-up you may or may not get. I must add that personally, it ended up making the conclusion to the first game on the show feel very anticlimactic, although I can see different opinions on the matter.
In the end, however, it all boils down to what
bayoab said a few pages ago
here.