Do you want your work to be closer to art pieces or practical-engineering products? When I want to design something, I do it in a rather practical way, usability and efficiency in mind, the art component comes in second place. However when I want art, I do paint. Oil painting, watercolor whatever.
I think some designers almost completely leave practicality out, and just focus on aesthetics etc. And I like it too but not as a piece of industrial design but more as a form of art. The thing is maybe there should be a distinction between the two points. And maybe there is a distinction that I am not aware of. But as far as I see they are usually both called “design”. Sometimes I want to see pure fantastic design pieces, that has no connection with reality, but sources do not distinguish it from practical ones. And sometimes I want to see real, produced or producable , practical design, but sources do not distinguish it too. And I hate seeing some concept with flying wheels and holographic signs when I want something real.
Why did I write these? I don’t know.
It doesn’t have to be an either-or situation. It can be well made, functional, serve a user need, satisfy a creative desire, AND impact the culture at large.
The four legs are:
- solves for a user need
- is manufacturable and sellable
- satisfies a creative desire
- impacts culture
I’d prefer 100% functionality and no “vs.” at all. If the product is intended to function as an arty object, you’re free to make it arty 
It makes no sense defining an art/practicality ratio because there is no trade-off like this: you could possibly reach perfection in both areas in the same product. Despite that, ratios like 60/40 would be neither applicable to different kinds of products nor measurable.
well for some people great practicality means work of art 
I put a little more definition around this framework here:
The most general answer I could ever give: it depends! 
But it really does. When I was doing research work for the University, everything was about experimenting.
Practicality always came second during the early stages of work, whether I was working on an application, an interface, or
something else entirely. Developing something interesting was the key.
The later stages of work, however, revolved around picking the most practical prototyped work to actually be developed properly.
Since design in general is all about solving a user’s need, it has to be practical eventually. I find this the most interesting and challenging part
of design - actually making things practical for everyone, not just for you.
But I don’t think we could answer your question before drawing the line on what’s “design” and what’s “art” on a specific project.