The beauty is indeed the ease of entry through almost instant gratification, which is critical. The beast is that erroneous progress will lead to a point where there is no more sustainable growth possible without a significant amount of unlearning of bad habits.

The mastery of bringing on new technology is understanding when the beauty is about to become a beast, and being able to apply some retro-active rigor at that stage.

Retro-active application of stricter development rules presents issues when not all individuals in an organization have enough skills to make such a step.

The cascading style sheets (CSS) progression mentioned is a good example. Applying cascading style sheets on top of HTML containing bad habits will progress slowly, and possibly halt CSS adoption due to the lack of timely successes. An effort will have to be made to refactor HTML to instill proper use of in-line style attributes, span and div, and so on.

The skill progression with cascading style sheets will be rewarding as described, if all HTML developers follow the necessary rigor.