USB flash drives automatically mounted (headless computer)

For the project SamplerBox, up to now I was using /dev/sda1 /media auto nofail 0 0 to have USB flash drives automatically mounted when inserted on the headless computer, see also Auto-mount and auto-remount with /etc/fstab. But this seems not very reliable, for example, when an USB flash drive is removed, and then re-inserted.

Are there any drawbacks from using mount –bind as a substitute for symbolic links?

Symlinks have limitations in how functions like ls, mv, and cp can operate on them because unlike shell initiated commands like cd, these functions do not have information about how the user accessed the directory with respect to the logical path (see related post). It seems like using the mount --bind option instead can get an around this, offering increased functionality and compatibility with samba and other file servers because the mounted directory will then have two independent physical paths, instead of a link.

Why does one need a loop device at all?

I previously used to create image files using dd, set up a filesystem on them using mkfsand mount them to access them as mounted partitions. Later on, I have seen on the internet that many examples use losetup beforehand to make a loop device entry under /dev, and then mount it. I could not tell why one would practically need an image file to behave as a loop device and have its own /dev entry while the same behaviour can be obtained without all the hassle.