On the Mac side iTunes is hardly bloated, on Windows it’s another story. Mostly because it installs so much extra, although I believe in the newer versions they give users more control. It should not be necessary to install bonjour, auto-updater, iOS connection drivers etc. unless you want it.
So what is iTunes (the app) today? It is basically a media management software. It contains its library functionality, media server, store access as well as access to the streaming service Apple Music and Radio. It is in a more or less unified way. But on top of that are the iPhone/iPad/iPod management software. Syncing from its own library makes sense, but backup and other control settings should really be somewhere else.
iTunes used to include iOS apps and books before. But the book reader was subpar and the apps were only for syncing purposes so it made sense to move them somewhere else.
Here comes the philosophical question, there are benefits to having separate apps for playing each “media”-type, but the unification if you want some organisation has crucial benefits. Especially if you want to store your files locally for serving media files on your network, or a single place to manage your device media syncing.
Of course for some online streaming is good enough, but the quality is a compromise and you are dependent on a working high speed internet connection at all time. The availability of what you want to stream are fully depending on the streaming provider as well.
If you look at Apple Music they limit their quality to 256kbit/s AAC. For the most newer and very mainstream pop music the metadata is correct and artwork is of decent quality. But as soon as you are venturing outside, the artwork is more like a scan made by a drunkard including the alcohol spilled on the cover. The metadata are with spelling errors or plain wrong. And tracks will be missing because of curious and ridiculous rights issues.
With video formats it is even more difficult with streaming. The bandwidth is rarely good enough for high quality modern formats, unless you are satisfied with the blockiness and other artefacts from the heavy compression. And then there are not enough bandwidth from your streaming provider and you are downgraded to 360p video and webcam sound.
iTunes have had its fair share of bugs, but finally I rarely discover issues. So it is ironic that when the software reaches maturity that Apple will change everything. Now I don’t know how and what parts of iTunes Apple plans to retain, so I will wait and see. There may be reasons to celebrate or great sorrow or something in-between.
But because it fits your usage, do not expect everyone is doing things your way.