Given that you already have dozens of site with their own passwords, you just can't import your passwords, but you need to change all of them to start using lesspass first.
Also, if the way the generation of passwords works changes later (i.e. bug), then the users are stuck with a version, or the bug is never fixed, ever.
You suddenly realize how many services have special rules you can't fit in. So for each service, I had to remember master password, which "url" i used (gmail.com or mail.google.com?) and which restrictions apply. Usually they did not allow me so long password. Sometimes I was limited to 16, sometimes 12 chars.
After big password leak (heartbleed), I had to setup second master password for all affected service.
So, no. No more sync-less state-less password managers for me.