It really isn't. "Scientific code" isn't some separate thing.

The only way it can help is if you're trying to write code that matches equations in a paper that uses 1-based indexing. But that very minor advantage doesn't outweigh the disadvantages by a wide margin. Lean doesn't make this silly mistake.

> If you really need the first or last element

What if you need the Nth block of M elements? The number of times I've written arr[(n-1)m+1:nm] in MATLAB... I do not know how anyone can prefer that nonsense to e.g. nm..<(n+1)m

I find it to be substantially worse. It's fine as long as you don't manipulate the indicies. But as soon as you start doing math on them 1 based becomes a headache (at least IME).

Meanwhile all you get in exchange (at least as far as I can tell) is ease of speaking about them in natural language. But I'm not usually conversing about indicies.

Concise range notations are a mixed bag. There's pros and cons to either scheme there as far as the syntax goes.