They are affordable and easy to use
Since youre still drawing fewer cards than everyone else, there are other applications involving hand size that are interesting: When youve made a hand out of your library, keeping your actual hand empty is easy
At roughly 1 SP per 12 boxes and six different SP types, targeting a specific SP like Nami means roughly 1 in 72 boxes similar odds to the Manga Rare itself
Constructed : As dragons aren't really popular in a lot of the 60-card formats, Maelstrom of the Spirit Dragon isn't seeing a ton of play
I wouldn't want to go too deeply on something like this, but a fun-of, one-of can go a long way
Overlord of the Boilerbilges can either be a 6-mana 5/5 red creature that can remove something (or hit face) with its attack trigger, or just a burn spell for 4 mana