Crossover is the commercial version of the code behind proton, developed by the same company. It doesn’t work as well on Mac as on Linux. Since “Like Linux but worse” is exactly the point you’re responding to, so you’re pretty much in agreement with them?
Any cryptography you’re likely to encounter uses fixed size primes over a residue ring for performance reasons. These superlarge primes aren’t relevant for practical cryptography, they’re just fun.