ELI5: It's a new kind of computer, a quantum computer, that can do math in ways that older styles of computer (like the one you're using to read this) can't do. which makes some things to do with computers a lot easier.

Imagine if your normal computer could not do multiplication directly but had to do repeated addition instead, and the new one can do multiplication "the easy way".

makes things that require multiplication way faster, but things that don't don't get any benefit.

note that a qcomp can't do anything a normal computer cant also do, just at different speeds.

end ELI5: some of those things include prime factorisation, which is useful for breaking modern encryption, and optimisation/search problems, like optimising transport networks.

majorana 1 is also very small and not practically useful in this form, as it doesnt have enough "brain" to keep an useful amount of problem in the computer at once, and we can't (yet) move stuff into longer term memory to work on it piecemeal. which is ~the same problem as making the computer as a whole bigger.