Smarky runs as a service.  It is triggered by a launchd task.  You should leave it quit except when you are doing bookmarks housecleaning.

If you change your Safari bookmarks while Smarky is running, Smarky will complain and insist that you perform the import manually, to avoid conflicts with whatever you may be doing in Smarky.

Hello, Trekker.

Thank you for contacting us.  The term syncing in Smarky is a little misleading because actually it only syncs itself with Safari on the Mac that it is installed on, which is what you want.  When you switch on the Syncing button in Smarky, it keeps your bookmarks sorted without you needing to manually import and export.  Smarky does not sync with Safari on any other devices.

The only service which can sync Safari bookmarks among devices is iCloud.  Smarky will work in tandem with iCloud.  Here is how: 

• Say you add a bookmark to Safari on your iPhone.
• iCloud will pull the new bookmark into iCloud.
• The next time your Mac is awake, iCloud will push the new bookmark to Safari on your Mac.
• A few minutes later, Smarky will pull the new bookmark into Smarky.
• Smarky will sort your bookmarks, putting the new bookmark into its proper place.
• Smarky with then export the sorted bookmarks to Safari on your Mac in such a way that iCloud notices.
• iCloud will pull the sorted bookmarks into iCloud.
• The next time your iPhone is on, iCloud will push the sorted bookmarks into Safari on your iPhone.

You see, it takes a while, but if you use your Mac regularly, it works.  It is the only way to have sorted bookmarks on, say, an iPhone, because Apple does not allow any app except Safari to directly access Safari bookmarks in iCloud, and on iOS devices Safari bookmarks are not accessible to other apps in any way.

Regarding crashes, there are no known crashing issues with Smarky, so I'd like to get a report.  To send a report. activate Smarky and click in the menu: Help > Trouble Zipper.  The more data you include, the better.