its never been a concern of mines.
1) i regularly backup my phone contents in case of a phone crash. because the is no such thing as safe mode on a phone and it wont automatically get picked up as a usb device if it cannot turn on.
2) the more full your phone is, the slower it gets over time. there is a reason your device isnt as fast now as the day you had it. more data to process, more thumbnails to generate. etc etc.

however, unless the new phones are taking 4k videos and have some other kind of encoder that uses 100mb/min i can understand why so much space is needed. the other positive of having such a huge amount of storage is if it can bebefit from running a full OS installation of windows/linux + dex meaning you have a full pc in your pocket meaning you dont have to sync things across multiple devices. you literally have it in your pocket.