The sign-up wall is the actual difference
Shortening a URL is a ten-second job that people need a few times a month, usually mid-task - putting a link in a slide, a printed handout, a message with a character limit. Requiring registration for that turns ten seconds into several minutes and an email address you did not want to give.
Softland treats a short link as something you make, not something you have an account for. You paste a URL, choose a slug if you want one, and you have a link. The management token that lets you edit or delete it later is kept in your browser, which is what makes ownership work without a password.
What "kept in this browser" means, precisely
The link itself is a normal server-side record - it has to be, or it could not redirect anyone. What lives locally is the secret that proves the link is yours, and the list of links this browser has made.
The consequence is worth stating plainly rather than burying: clear your site data, or move to a different device, and you lose the ability to edit those links. The links keep working for everyone who has them, but you can no longer change where they point. For a link on a printed poster, that is a genuine reason to prefer an account-based service.
Tag the link before you shorten it
Whichever shortener you use, a link shared without campaign parameters arrives in analytics as direct or referral traffic, indistinguishable from everything else - which is how a campaign ends up appearing to have done nothing at all.
Build the parameters onto the destination URL first, then shorten it. The tags survive the redirect, so the link you hand out is still short and the destination still knows where the visit came from.