This is a user-to-user forum. You are not addressing Apple here.
This feature helps users not being tracked through their MAC address across various Wi-Fi networks. That’s all. Not a network security concern by itself. I would argue that neither the device user, nor the network have diminished network security because of this. And I’m happy that it is available to me. Devices would still use a single address for each network (unless more than 6 weeks ago). Re-connecting to a previous network would then use the same old remembered MAC address again.
Other non-Apple devices also have this ability, in some shape or form, so networks will have to deal with this regardless of Apple’s policy.
The feature can be turned off, so it is 100% optional.
Learn more about it here:
Wi-Fi privacy - Apple Support
Use private Wi-Fi addresses on iPhone, iPad, iPod touch, and Apple Watch - Apple Support
You’re not doing network access authentication by MAC address, are you? That would be a security concern. It is relatively easy for someone to capture/discover and clone/mask/spoof MAC addresses, which is why they shouldn't be used for security.