The benefits of disabling Windows Update and Defender is substantially reduced resource usage, as well as preventing tweaks from being reset to default or components being restored. Another benefit is you don't have to deal with the bugs that are introduced with updates (
link), which is a problem that has been frequently covered in recent years by every major computer news site. You really aren't missing out on new features or improvements to Windows from updates, so long as you're using a stable version to begin with, because the quality control from Microsoft these days just isn't very good.
The main thing is, it's kind of pointless to use NTLite to do any major tweaking, if you're just going to leave Windows Update to do whatever it wants. Modern operating systems have reached a point where the user has lost too much control, and the amount of effort required to gain it back (tweaking) just isn't worth the hassle of then dealing with updates constantly interfering with that.
Me personally, what I settled on is to download the new ISO from Microsoft that they release once a year, and if it's stable and has good performance, I use NTLite to add all my tweaks to it and cleanly install Windows again. These ISO releases contain all of the updates that occurred in the previous 12 months. Sometimes a version is botched, like 22H2, which has too many bugs for my liking and so I skipped it and will wait for 23H2. Other people like to use NTLite to manually install updates, since it gives them more control.
There are some important things to note about uninstalling Windows Update and Defender. I would personally suggest pausing Windows Update forever, instead of uninstalling it, because there are a number of dependencies related to it that I don't think are worth the headache of dealing with. Defender I think can be uninstalled without any issues, aside from a problem that NTLite causes, which is that NTLite doesn't separate out the files as it should, and so the Security Center gets uninstalled along with Defender. That's a problem because that interface has options which someone like a gamer needs to toggle, and unless you have a deep understanding of the registry it's too difficult to manipulate without the interface. I use registry keys to handle Windows Update and Defender since it's far safer and just as effective.