As a general use seal, no, as most units that use it, if they're not fast, will be forced to run Desperation in tandem with it, and getting to that point safely is not consistent enough to warrant doing so. And without Desperation, they'd run the risk of dying before being able to get their second hit off anyways in most cases. Micaiah is one of the few units that actually could use it well on PP specifically, but majority of her builds shifted to being a counter to cav lines in AR as of recent, moreso after her prf refine, so they're generally more EP focused now.
Female Corrin is considered as a carry unit, so you'd want a Smoke skill on her C to benefit from her prf/ability to debuff on EP to be able to tank more on both phases. Mostly supportive units would want supportive skills, and again, by doing so, you're further restricting your comp choices/consistency.
That's why I stated that Distant Guard, while not universally useful, still has a strong niche, moreso at a 3/4* availability (with feathers).
Joint Drives are the more common meta C slot skills since they're universally useful in almost every comp and even benefit the inheritor of it (ignoring Galeforce units) as long as you can manage the proximity of the buffs well.
Yeah, I don't know why they are still giving those types of skills either to newer units, but as she was the demote, that was expected.
With how strong the Save skills are, if you ever plan to build an armor unit in the future, you'll probably want to get fodder for them specifically, depending on their stat-spread/build, but that's up to you. They're essential to almost any armor unit that doesn't have the one they want in their base kit.
Generally speaking, building any unit can be considered as "expensive" ignoring the builds that I mentioned earlier, so it's just a matter of deciding what is worthwhile for your orb investment to be allocated towards.
Codes help a bit, but they're not enough, to me anyways.