I mean, E2E is the entire point of Signal. if you don't think E2E is important then Signal is the wrong app. Personally given the current political climate I think having the technical knowledge to understand what E2E is and not wanting E2E is bonkers. High chance of people getting killed or jailed in the US for mainstream political positions in the near future.
For those to be equal you need both associativity and commutativity.
Commutativity says that a*b = b*a, but that's not enough to allow arbitrary reordering. When you write a*b*c depending on whether * is left or right associative that either means a*(b*c) or (a*b)*c. If those are equal we say the operation is associative. You need both to allow arbitrary reordering. If an operation is only commutative you can turn a*(b*c) into a*(c*b) or (b*c)*a but there is no way to put a in the middle.
That era was nice but it has a different problem. People will pearl clutch about kids getting exposed to someone's custom skin making their character nude, or putting curse words on the side of a gun or whatever.
This would be a huge deal for Python startup time *if* it was applied to all the standard library packages recursively. Right now importing asyncio brings in half the standard library through transitive imports.
Context switching makes you less productive compared to if you could completely finish one task before moving to the other though. in the limit an LLM that responds instantly is still better.
You're a bit naive about the complexity. Commonly longer sequences are actually faster, not just because instructions vary in their speed, but also because the presence of earlier instructions that don't feed results into later instructions still affect their performance. Different instructions consume different CPU resources and can contend for them (e.g. the CPU can stall even though all the inputs needed for a calculation are ready just because you've done too many of that operation recently). And then keep in mind when I say "earlier instructions" I don't mean earlier in the textual list, I mean in the history of instructions actually executed; you can reach the same instruction arriving from many different paths!