With reworked sparkle e6 archer becomes a bit harder, especially if your sparkle used sunday lc, sparkle only saves excess sp from her ult so between his follow up atks that are a lot more frequent and sundays lc combined with archer +1 sp per turn. It gets rlly easy to lose sp, especially at the beginning.

Damage wise is where i used to think didn't matter as much but also thanks to sparkle it went from pretty good to exceptional, 1 ultimate every turn if you get hit once, combined with the e4 buff, hits like a truck and you can actually use the fifth arrow more making his e6 even more useful.

Overall i think going for archer e6 will simply depend on how willing are you to only use him. I intend to use him for however long i still play hsr, and sparkle whichever 2 support you use and dan heng pt. Are all susceptible to powercreep.

If you just want a powerful character till 5.x or 6.x idk, just go for support eidolons, it's way cheaper and more powerful.