Is summer banner worth it?

Archer Artoria is pretty great, and Ruler Martha has her niche too, and they'll be part of the same summoning banner in the 2nd part of the event.

I was the guy who asked the question about Archuria. I've been doing some more research and imo it's probably not worth it. Kuro is decent enough at np spamming (her NP5 damage will outdamage Archuria NP1) that it isn't worth using your SQs trying to get archuria. Tamamo isn't good enough to be worth rolling for over the Bryn you already have (not to mention Bryn gets a big buff in two years if you wanna look that far in the future). I think it's more worth to save for some of the more interesting servants in the future (ex. King Hassan, Merlin, etc.)

While there are some very great servants whether or not it's worth it depends on two things: What servants you have and if you like the servants in general.
Archuria is a great servant, essentialy power creeping Orion as the go-to Arts-based single target Archer (though Euryale being easy to get and NP5 is still worth it) considering she can spam her NP, Kuro is also a Single target arts based archer that can spam her NP pretty well, and is a welfare servant that you WILL NP 5, unlike Archuria who you'd be lucky to get her at NP1.

Tama Lancer hits hard as a Lancer, but Byrn, Scathach Cu, and Li Shuwen exist, with Cu and Li more available. In fact, I think Byrn and Scathach has more rate-ups.

Ruler Martha is TBH is the only one worth going for.

Kuro is a Welfare Servant, so you can get her for free. In your case, it sounds like Ruler Martha probably would be your best bet and is also a solid choice to aim for.

She is an offensive Ruler with a Berserker style layout (4 Busters, 1 Arts, 1 Quick), and accounting for the Ruler attack modifier, also has one of the highest attacks among 4 star Servants. On top of her Ruler class, it means she takes half damage from everything that is not Berserker or Avenger (The latter is very irrelevant). Although she would be dealing Neutral damage to everything, her high attack with natural tankiness allows her to beat them up.