I don't use the
discard mount option for any filesystem. btrfs has the option
ssd for SSDs (which is btw autodetected and automatically enabled).
Not because out of fear for performance issues, but because I don't think it's need. All modern Linux Filesystems accommodate for Solid Storage Devices, some better than others. And the Firmware of SSDs does what it wants anyway.
Currently the kernel folks are working on async IO, one of the fruits is for example is "async discard" for btrfs with linux 5.6. But "online discard" how we expect it to be will only happen after all filesystems have accomodated for async IO and the FIrmware of SSDs plays ball with it. Until then, a systemd-service with
fstrim is all you need.