George alludes to good points; and I think the biggest point in favor of not learning to rely on jigs is that that development of skill will allow you do lots of other amazing things; often things that you can't accomplish without jigs, or at least without spending more time on jigs and guides than the actual project. Learning to saw dovetails by hand is going to be a great part of learning how to cut things by hand; once you can do that, you find you can do things like odd, compound cuts on oddly shaped pieces that would require complex jigs and work holding if you were trying to make it work on say, a table saw. Once you learn to sharpen freehand, you learn to be able to sharpen lots of things that will never fit in your honing guide; etc., etc. If you have no interest in learning to craft things by hand, and just want some drawers, maybe a dovetail guide is a good solution. But if you purposefully don't expand your skill set, but want to continue creating things, eventually you may very well find yourself banging against a wall you were ill-prepared for.
" Be willing to make mistakes in your basements, garages, apartments and palaces. I have made many. Your first attempts may be poor. They will not be futile. " - M.S. Bickford, Mouldings In Practice