I used neither python nor scheme myself, but would add some general thoughts anyways:
Many "modern" languages are in fact "multi-paradigm", thus offering constructs for functional, imperative and object-oriented styles, leaving the choice to the programmer. These languages often become somewhat popular for their versatility.
It even makes sense to "mix" paradigms in the same codebase. As an example, functional and object-oriented programming doesn't have to be mutually exclusive. Applying both just means that the objects are the (immutable) values handled by functions. There's still something to gain from "member functions" (methods): You'll still have functions "mutating" objects, but instead of doing that directly, they create and return a modified copy. These are still logically tied to the object type, so having them as member functions there helps the structure of your project.
Of course, that's different from the original OOP ideas. Code reuse by inheritance once was considered a great idea, now we know it just leads to unmaintainably complex object graphs, and when you add the directly mutating methods to that, you'll have bugs by the dozen.
In theory, you can program anything following any paradigm, but still, some are better suited to specific tasks than others. Take for example some GUI logic: Almost nobody would want to use a strictly functional style there. It's possible, but as soon as you need "side effects", the functional style gets very cumbersome. You will mostly use some OOP style for GUIs. OTOH, for your "core logic" (what the program is actually doing), you should separate that from layers with side effects (like UI, persistence, ...) anyways, so very often, doing it functional is the best choice there is. Even a language like C++ added constructs (lambdas) to enable some things functional, although it isn't complete there.
As I said, I didn't use python so far, but assuming it has somewhat sane support for different paradigms, that might be a reason for popularity. Having to learn just a single language and not having to think about integration of parts written in different languages is a big plus for a software project.