it's a very interesting spot she's occupying. Setups too long for speedrunners, HP drain too uncomfy for casual players. And all around there aren't many role consolidators right now that satisfy her particular team needs (healing, grouping, interruption resist). I imagine future characters will be sold to fix that issue.
Unfortunately since the cost system is a community-made concept (that happened to work decently well for normalizing investment level), it was always going to be tenuous whether new teams would do well in it. Low cost teams thrive on abusing the efficiency of 4* on the level of Bennett/Xingqiu/Xiangling/etc. But since mihoyo have been releasing fewer and fewer characters of that caliber, Furina teams weren't guaranteed to get good 4* role consolidation so that she can compete in lower brackets.