A potential problem with the force-disabling in 57 is that the only way to hand over configuration from a legacy addon to its successor WebExtension is to preem

A potential problem with the force-disabling in 57 is that the only way to hand over configuration from a legacy addon to its successor WebExtension is to preemptively for the legacy addon to convert their configuration. If you only irregularly use your Firefox, the configuration conversion is not guaranteed to run, as you would have to open your Firefox to trigger that.