There is much important work written in Weil's language of algebraic geometry rather than schemes (besides Weil himself, I can think of Shimura, Neron immediately).

My question is: is it worth the effort (e.g. time) to read these? This, at least seems to me, to fall under the umbrella of "reading the masters".

I have realized that this question is a little broad, indeed much broader than some related questions like

Scheme theoretic interpretations of the Weil's foundations of algebraic geometry

Some arithmetic terminology: "universal domain", "specialization", "Chow point"

where some specific parts of Weil's language are discussed. But I do not want to miss the beautiful mathematics in these work, and I am not an expert to be sufficiently informed.

From the related questions above, I understand that at least parts of the Weil language have been subsumed by e.g. SGA. But how about other important work e.g. Shimura's? (again, not an expert myself, so I can only think of Shimura/Neron; and Neron models have been addressed in scheme language) Translating it on-demand also requires actually understanding the language.

Background: I might as well ask the question on math.stackexchange, but I am thinking maybe mathoverflow is a better venue given the different types of questions asked at the 2 places. I am in the learning process hoping to reach research-level in arithmetic geometry; in this direction: have gone through parts of Hartshorne/Mumford-Oda/Liu/Vakil's notes/Gortz-Wedhorn (yeah, AG is not easy for me, I have to learn from different sources), and some number theory from Neukirch's book, in the process of reading Silverman's books on elliptic curves.

Thank you very much!