Search engines index the page a link resolves to, not the shortener URL itself. A properly configured 301 redirect (the kind Linqeezy uses) passes through cleanly — there's no meaningful SEO penalty for using a shortener on your own marketing links.
What actually does hurt: redirect chains (a shortened link that redirects to another redirect before landing on the real page), slow interstitial pages between the short link and the destination, and links that don't preserve mobile deep-linking. Linqeezy redirects in a single hop with a real 301 and no interstitial page — the version of "shortened link" that doesn't have a downside.
The myth that short links add ranking value is also false, for what it's worth — a link doesn't get better or worse for search purely because it's shortened. What matters is the destination page itself.