What is the point of 'sync music' in iTunes if I have to click 'make available offline'?

Used to be, I bought music in iTunes and then sync'ed it to my phone. If I didn't have enough space on the phone, I'd only sync certain playlists. Then I always had the music on my phone, even if in airplane mode or off wifi. Now I do that but it doesn't sync all the music. Apparently I have to go to each playlist on my phone and click 'make available off line'. This is tedious as I have numerous playlists. (But it is not all my music that is in iTunes, because I don't have the space on the phone.) So if I must do both, I must consult the list of playlists that have been sync'd, open each one on the iPhone and click 'make available offline'.

I am often not on Wi-Fi, for instance if I'm driving or taking a walk or on an airplane. Why should most of my music cease to be available? This is music I purchased. Why is there an implicit assumption that we are always on Wi-Fi?

Question 1: What is the point of having both 'sync' and 'make available offline'?

Question 2: Is there any way to just use 'sync' and have the music behave as before the advent of iCloud, ie. be available on my phone regardless of whether I have Wi-Fi?

I hope you only use iTunes purchases not Apple music.

So the answer for your first problem is,

that If you sync them, they will be available on all of your devices. However, making them available offline means that you can listen to your music wherever you go. You do not have to be connected to WiFi. So sync only add them to your Music app automatically. Point is that some people don't have enough space to download every song since their library is like 20GB. So they use Wi-Fi to download their song when they needed.

Answer for second question :

So as far as I know , they now use iCloud to sync all of your music to your every device through iCloud. So whenever you purchase some music it will automatically being available on your iPhone. Then you have select download if you wanna listen offline.

If you like to make them automatically download to your phone without touching download for every single song, just goto Settings -> Music -> Under downloads turn on "Automatic Downloads" . That would automatically download your songs.

Since you have DRM enabled songs on your device ( Purchased from Apple) you cannot simply do whatever you want. If you want to play with them as before they use iCloud, you have to manually download that song from internet and add them to iTunes. Then sync to your iPhone. Otherwise as Apple Supportive person told me there will be no option because, you run out of space.

If you don't like to manually do what I said, you have to do keep itunes purchases only synced. But that will not solve your problem. If this ain't clear enough just add a comment. Thanks.