Recent Epson pro printers have proven to be quite consistent when new across the line. The way it should be.
It's not when the printers are new that there is a frequent need of calibration , but one that has been seen as necessary further on and also with environmental changes, more so media changes.
Many users have noted variations when production tolerances are best controlled.
Even though it is better to maintain a tight tolerance, it really is up to the user to determine their own tolerance levels. IF you print the same image a year later and the delta E is around +/- 2 it's probably not that important, to most that is.
Those printing for galleries though should be maintaining their printers with calibration and verification. So for them an on board spectro is very good thing.
This can be done manually, as it has been done in the past. An on board spectro is the most reliable error free way of maintaining calibration and verification.
It is an option that will make fine art and proofers very happy, but is not a strict requirement for people printing one offs. Fact is the inter printer differences would probably be unnoticed by most between print runs as well, hence Epson insisting it was not necessary. How they translate that in their marketing is absurd trying to say that because their Piezo heads don't need it is rather an strange way of justification. Yet Epson always say the new printer is the best etc etc , making the past best no longer valid.
I hope this makes sense and the only point that was made was one of Epson's marketing speak.
Nothing wrong with liking the product, certainly not the new propositions, it's best to competition the marketing lines that are changing their tune just because they don't like healthy.