There are several advantages to not having them: without all the extra parts needed to support these features you can make the phone thinner (thickness is traditionally a key marketing point for smartphones) and cheaper to make.
Additionally, it seems that a lot of people no longer need these features, making them prime candidates for exclusion: Bluetooth headphones have become very common, internal storages have become large enough, and people buy a new phone often enough nowadays that battery wear is not as much of an issue.
Of course, if you are one of the people who still do want these features you’re pretty much out of luck. Which sucks.