Much too often people end up in a static state in their work. They might do their job and maybe even do it very well to the needs of the company for which they are working but a lot of people don’t develop themselves anymore.
To be able to develop yourself you need to step out of your comfort zone. It is comparable to physical training. It doesn’t matter if you are training for a world record on the marathon or just want to extend your weekly recreational run from 5km to 6km. If an athlete will run a marathon at the exact same pace as he is used to, he will probably never be able to break the record that he wants. He will need to stretch beyond the capabilities of his current strength and stamina to achieve what he wants to achieve. This will hurt in the beginning, but will make him stronger and achieve his goal faster.
Self development of people in their line of work works in a similar fashion. The best way to develop yourself is to step out of your comfort zone and use tools, technologies or approaches that you are not used to. Just as with physical exercise it will hurt and initially you will probably do your work slower compared to how it would be when staying in that nice comfort zone. And there is even the risk of not being able to complete your work at all because your experiment dit not work out the way you wanted it. But in the end, you will have learned and you have improved yourself.
So as a manager which people do you want? Which people will bring your company further? The people that will stay safely in their comfort zone, or the people that will take a risk from time to time? The second group of people will definitely make some of your iterations fail, but in the end they will also realize the improvements that your company needs to gain an edge of your competition.