In gawk I know two ways to test if a string contains a number. Which is best?

Method one: using regular expressions:

function method1(x) {
    return x ~ /^[+-]?([0-9]+[.]?[0-9]*|[.][0-9]+)([eE][+-]?[0-9]+)?$/
}

Method two: the coercion trick (simpler):

 function method2(x) {
     return (x != "") && (x+0 == x)
 }

Is there any reason to favor the more complex method1 over the simpler method2?