Evil or awesome use of tags in golang for debugging?

bench.sh

#!/bin/sh
go test -test.bench . 2> /dev/null
go test -tags debug -test.bench . 2> /dev/null

bench_output.txt

PASS
BenchmarkDebug  100000000	        13.3 ns/op
ok  	_/home/shane/projects/log	1.356s
PASS
BenchmarkDebug	 2000000	       839 ns/op
ok  	_/home/shane/projects/log	2.541s

log_debug.go

// +build debug

package log

import (
  "fmt"
  "os"
)

// Complicated as you like, include line numbers and such.
func Debugf(format string, v ...interface{}) {
  fmt.Fprintf(os.Stderr, format, v...)
}

log_nodebug.go

// +build !debug

package log

// Just a stub.
func Debugf(format string, v ...interface{}) {}

log_test.go

package log

import (
  "testing"
)

func BenchmarkDebug(b *testing.B) {
  for i := 0; i < b.N; i++ {
    Debugf("test")
  }
}