Back to ACP's question in the OP, it seems reasonable enough to assert that using a DBM has its benefits as outlined by several posters who use them to positive effect in hunting, target, and gaming applications. While some of us prefer (or are too cheep/obtuse to see these benefits) internal magazines, ultimately the individual must make the tactical decision that suits the rifle's purpose.
Maybe we could define tactical as purpose-built for practical application during hostile or volitile combat scenarios. OR...or we could all eat Lucky Charms knowing full well what was meant. I've used many an improvised hammer and never was it tactical!