As a Talent Manager behind some large channels, scripting can be a huge help, and it can be a huge hindrance too.
I find sometimes it can be better to bullet point your key beats and then flow naturally into the conversation, you retain your normal speaking voice instead of the awkward reading voice many have. This creates authentic VO and retains those key beats.
However, scripting can be very useful when you are delivering the perfect beats and tone when you have something you have to say in a specific way, be that an ad read or facts in a documentary and you need to sound authoritative and precise.
Without a script you can say whatever you like, however you like, and it can often be the right way to go for an informal and relaxed feel, or if you know your stuff it can demonstrate that with the natural tone your audience loves
TLDR: It's all about what you are making, the tone and the formality.