Is Eirika still worth it?

Mmmmm. To be honest there are too many sword users and most of them have like legendaries weapons with distant counter and everything, so she can be out closed to be honest. We have too many red units, that's a problem I think.

ehhh... depends on team comp. if youre fine running a more physical red (think ike, ryoma etc...) and you have a blade tome unit on your team, she can be a nice asset as she can buff all 4 stats at once if built correctly. overall, i like her but the amount of inheritance ive used on her is ridiculous. so idk up to you. she synergizes best with blade tomes and thats where im going to leave this.

Eirika's major niche is buffing blade tome users...but visible buffs have been getting major nerfs lately. I'm not sure how big of an impact the Panic Ploy seal and Halloween weapons with "Panic Smoke" are going to have but it's likely to hurt blade tome users.

In any case, Eirika herself is more usable as a standalone now that Deflect Magic 3 is a thing. Check out the question two down from this one, it's all about how -RES Eirika can now tank Reinhardt.
https://fireemblem.gamepress.gg/q-a/correct-me-if-im-wrong

I have the same IVs and am thinking of promoting her. With Fury 3 and the attack +3 seal she has 48 atk and 41 speed. Basically the same stats as Anna. TA3 might be the better way to go though since BIke is on almost every arena team now. She is probably only worth it because it's easy to get multiple copies of her and merge for a better arena score.

My only worry with Eirika is that she's one sacred seal away from complete irrelevance (hone speed or hone attack). We already have the fortify seals, once they release hone seals, with the opposite hone c slot & Rally Def/Res being 4* available, there'd be no reason not to just run Ryoma/Ike/Ayra as an infantry sword wielding buffer, not to mention all the other unit types which could be utilized that way.

Besides that, infantry blade mages (the primary beneficiaries of the bufftwins) have largely declined in viability sans Nino I guess... same with hone/fortify effects over drive/goad (aka spurs) imo, outside of cavalry or I suppose armor teams.