I'd rather practice and give the missing bit a miss!
How to best practice is also often an issue in elite sports, and there still isnt any fully clear consensus i think.
Personally i think the student(s) of a given skill or skill set is normally best benefitted from starting in a difficulty and complexity wise less difficult and simplified enviroment vs what is the end goal of the learning process.
An enviroment where it is possible to, with less stress and things to keep an eye on, focus on the different parts of the skill one is trying to learn, and to then build those up with an eye for detail and quality.
As one gets better, more and more elements of the complete movement/skill should get added and the difficulty level and complexity level should get raised too. This should be done untill you're faced with executing the complete skill in it's real intended target enviroment. Or as close as it is possible to get in your training enviroment.
At that point it's time to hit reality, which is, in a way, the ulimate and last part of the training, ie. using the desired skill set in its full and desired target enviroment. Because doing that, once you're ready, is of course what is going to see you take that last step, (inside the given limitations of your talent base, physical condition, time spent, quality of instruction given etc), and become a strong(er) performer of your skill in its real life intended circumstance.
So one needs the other imo if excellence is to be achieved, and training (well) and building skill sets in a controlled enviroment and becoming good at it in reality, are not enemies, but allies.
And besides the skill set building aspects of good training, there are social ones too. Training with good instructors or friends can often be good fun, and lead to new information or possibilities coming your way.
But each to their own of course! - we're all different, and good luck for that! I mean just look at
@Mike1979 , he owns a creedmore, and with it probably more beard and hair grooming products than the entire 270 shooting population of GB put together!! - and we dont pull his leg over that, do we ? (just kidding Mike, some banter to the right person is fine indeed for me

)
But joking aside, a lot of this comes down to subjective preferences, or difference in the knowledge base from which ones povs are shaped. That is fine, in fact it is interesting, and part of why many of us are on a board such as this, i assume. The important bit is just discussing our opinions civily, and hopefully making each other cleverer, smarter and better for it in the process. Oh and maybe have a laugh as well, from time to time. ,)