That is not a thing you should do even with OpenWrt releases. Although with a proper stable release there should be less upgrades than in a Release Candidate stage.
Please read this
Packages on OpenWrt exist mostly to let you add functionality to your device, not to upgrade the whole system.
You should update specific packages if you know you need it, otherwise the best way to do system upgrades is to download an image and do a firmware upgrade.
I'm not saying it's "a good thing" or that "you are using it wrong". I would prefer OpenWrt package management was more advanced and didn't just blow up like this, but this is what we have.