It seems Cursor is getting more and more complicated by updating to newer versions. But the most important aspects for me should be its coding abilities. I am currently still on version 0.50, can someone summarize the main reasons to update to the latest version in regards to enhancement in coding efficiency? Thanks.
Old versions do not get the new features but there are lots of new features coming 
which improve Agents handling.
Have a look at the Changelog if you need reasons why
In addition to the above, this also includes bug fixes and stability improvements. You don’t need to use older versions unless some functionality was broken in the new version and hasn’t been fixed yet.