Internet is heavily optimized, compared to Chrome or Firefox. It feels much faster in usage, and consumes much lesser battery. It has a lot of features too, so that is a plus. Oh, and they understand the advantage of a consistent, stable UI. Things don't move around for no reason from update to update. I love the reliability that provides.
I have exclusively used it for years, can't say that I've heard of any vulnerabilities that affect only Internet.
PS: funny that people are bashing Samsung on a thread with a silly Google bug. This is exactly the sort of thing that never breaks on Samsung devices. QR codes have been a solved problem for years. If Google cannot avoid breakage here, wonder what critical infra they keep breaking without us knowing.