if you have to solve mathematical programming/convex optimization problems, JuMP as a frontend for free or commercial solvers is hugely better than any alternative.
likewise if you are solving differential equations, DifferentialEquations.jl is hugely better than any free alternative I know of and arguably better than paid packages. The broader SciML ecosystem that's built up around this has a lot of cool stuff in it too.
other than this it seems like you wouldn't care about the other potential advantages, and might be more put off than average by the disadvantages and occasional rough edges.
likewise if you are solving differential equations, DifferentialEquations.jl is hugely better than any free alternative I know of and arguably better than paid packages. The broader SciML ecosystem that's built up around this has a lot of cool stuff in it too.
other than this it seems like you wouldn't care about the other potential advantages, and might be more put off than average by the disadvantages and occasional rough edges.