How do I find value in a non-native and seemingly pointless ornamental plant?

First post here, so sorry if I get it all wrong.

I'm in a rental house which I'm using as my first permaculture design experiment. I'd like to leave the property with better soil, more critter life and new (but low-cost) food-producing trees and plants. But it is a rental, so I'll also need to maintain the existing plantings and get permission for any large-scale changes.

The current plantings include a lot of common non-native ornamental species which I should maintain plus a few native, potentially more useful species that may be volunteers but that I'm choosing to believe were specially planted for me to care for and help thrive.

I have these nice looking shrubs in my front and back yards; I'm pretty sure they're Euonymus japonicus. They're pretty and inoffensive, but they also seem kind of pointless from a native-gardening standpoint. But they're growing incredibly well in my most-shaded spots, and I'm determined to figure out how they can be useful. Does anyone have either any ideas to use them, or even just a different way of looking at them as a benefit rather than just something I need to prune back occasionally? I guess I'm trying to figure out how to value and use everything I have rather than put them into "good" or "bad" categories in my mind.

I had a look at the Plants for a Future page on Euonymus japonicus

It says that young leaves can be eaten and that old leaves can be powdered and used as a food or yarn colouring, I think yellow. The fruit and seeds are reportedly toxic however.

And apparently you can extract a latex from the roots which can be used for making plastics and as an electrical insulator.

Google tells me that in some Asian cultures, the plant is utilized in traditional medicine and is believed to possess anti-inflammatory and antimicrobial qualities.

If they are growing that well, they could always be trimmed and used as mulch to improve the soil. Maybe use them as a base and plant more interesting things around them.

I suppose all "native" plants started either as non-native plants or else as different plants whose offspring evolved or were cultivated, in that locale, into the plants in question. So, just wait a few million years and then the lines around native and non-native can be redrawn!

Almost every plant has some value.

Euonymus japonicus is a very attractive plant.  It is pretty.

It does have some medicinal value.  

https://permies.com/t/229870/Medicinal-Shrubs-Woody-Vines-Euonymous

Like Anne said, it's a pretty shrub:  it grows where not much else will, and is growing well.  I believe it's an evergreen;  I have a similar one, but more of a creeping shrub, growing beneath a berberis;  I sometimes cut its pretty yellow stems to add to my homegrown bouquets.  

A garden of ornamentals still has value, in my opinion.  I have many ornamentals along with food producing plants, and they give me a lot of joy.  Here's a photo of mine from March.  

I think the fact that the plant is healthy and happy would be enough for me.  I have lots of plants that I put in just because I like them.  I can like a plant for all sorts of reasons.  Life is awfully short to have to justify just plain liking something.  for example, I love hot pepper plants.  The ones I am growing this year are far too hot for me to eat.  I'll try them in chili, using a small part of one pepper from a plant that will grow dozens of peppers, but the real reason I grow them is because I think they're beautiful.  Hot peppers come in so many colors and odd shapes and sizes that I'm just fascinated by them.  I grow them in pots so I can bring them in at the end of our summer and keep them alive for a couple extra years.  This year I'm growing tiberius mauler, chocolate reaper, scotch brains, and scotch bonnets.  They aren't really useful in any meaningful way, but I just really enjoy watching them grow and I love seeing the plants covered in strange and beautiful peppers.  That's enough reason for me.

I pretty much used to feel the same way until someone pointed out that usefulness has many facets. If a plant is pleasing and pretty, it's aesthetic value can be high even though it isn't edible, medicinal, or attractive to pollinators.Moreso if it's heat and drought tolerant and I know it won't die easily on me. All that can be important to my well-being. Some ornamentals make nice wildlife habitats, for example nesting spots for birds. Some can offer privacy or shade. Around a house, shading heat-retaining bricks from hot sun isn't a bad idea.