|Effect||Deal x Physical damage|
Typically, you don't want basic attack cards in your deck, and the strategy to using them is to remove them from your deck as soon as possible. However, you will need to use these as best you can to deal with the monsters on floor 1, and some decks are not as negatively impacted by the presense of basic attacks. For example, if you are able to acquire action cards like Sift, Inner Peace, Meditate, etc... that discard cards, then removing the basic attacks from your deck becomes much less important and the money / talents / level up bonuses that would have been used to remove attacks can be spent on other things. Also, warriors with Swords rely on playing attack cards (although they still prefer other attack cards).
It is almost never a good idea to waste an upgrade on a basic attack, although there may be a few exceptions (such as allowing Protean to trigger more often).
One strategy that can make use of basic attack cards is a deck based on Scimitars. For that deck to work, you will want a way to level up all of your attacks at low cost (such as being a Paladin, getting a Soulforge, or choosing the Heroic talent). A deck with multiple Scimitars and Swords can turn a basic attack into the equivalent of a Smash, or even be better than Smash if you have Sundering Strike!