Your investments in your own development are likely to accelerate your career growth. It is easiest to move on in your career when you have someone on your team who can smoothly transition into your role. So when you are selecting people to join your team, make sure you select some people who have the potential to be promoted.
Not every candidate will meet this standard, and not every person on your team needs to be promotable. When you hold to this standard for a new hire, it is likely to take longer to fill that position, but if you hold out for at least some promotable individuals, you will be taking care of your team's future needs.
A consequence of this approach is that you might wind up with more promotion-ready people than you have opportunities. You invest in their development, and then they leave for promotions available in other organizations. That is a great problem to have. You should consider those kinds of moves to be graduations. This is something you should be proud of and something you should publicize. You will earn the reputation of investing in people and preparing them to move forward in their careers. That kind of reputation makes it easier to attract more high-potential people to your organization.