Upgrading apps without Big Sur

Hello,
Just wondering if there is any point in upgrading apps if Big Sur is not installed?

Very likely there is. Most applications have feature enhancements and bug fixes in every version that’s put out. Of course some introduce new bugs. Without actually knowing what version of the software you’re talking about it’s hard to say. You could check the what’s new for recent updates to see what’s in them.

I have FC 10.4.10 latest upgrade with Catalinea.
Haven't upgraded latest version of FC.
Seem's like most new features require Big Sur .
I imagine these do not require Big Sur:

Final Cut Pro 10.5 also includes the following:

Export HLG high-dynamic-range projects with Dolby Vision 8.4 metadata for optimized playback on Apple Devices.
Fixes an issue in which LUTs were not available in optimized or proxy clips.
Improves appearance of HDR thumbnails in the browser and timeline.
Improves reliability when previewing built-in sound effects in the browser.
Fixes an issue in which audio waveforms would not update in the inspector after adding a filter or making a volume change.
Fixes an issue in which chapter markers were not available when sharing.
Improves reliability when creating proxy media from non-square pixel interlaced clips.
Improves stability when applying stabilization and color balance during import.
Fixes an issue in which audio sync could drift when retiming clips.
Improves reliability with Social Media content positioning when using Smart Conform to switch between vertical and horizontal frame sizes.
Improves reliability when using onscreen Crop controls in the viewer.
Fixes an issue in which copying stills between libraries would result in duplicate files.
Includes built-in support for Avid DNxHR® and Avid DNxHD® decoding and playback.

FCP 10.5 requires MacOS 10.15.6 or later, so you do not need Big Sur for any new features. It runs fine on Catalina.

Ok. Thanks to you both.
So I should be good.
My OS: 10.15.7

Just an aside, but in my limited experience, Big Sur is way more reliable than Catalina, especially FCP. (Note that Apple has dropped the "X" so it's just Final Cut Pro)

Disclaimer: your milage may vary, I am merely observing my experience