Unfortunately, Liana is the worst black to pull. (Berna is not a bad unit asdf)
She wasn't quite available at the start, but maybe a month or two after launch, along with Deine. She's originally an event unit, but was our replacement for black Iris.
As a result, it's impractical to mincost her and thus I find her too expensive to deploy over my plat healers, and I haven't even CC'd her because of that. If you don't have Camilla or Chydis, I guess she's fine, but otherwise, if you need range, just use Fedora, IMO. As for paralysis, any AW healer will do since they halve its duration.
Also, in the two events that we've had paralysis, I have not needed to use her skill. (Granted, I have several other plats/blacks, but still.)