It's essential, but even with it large packs of creatures like wolves or neckers, that would be nothing more than a trivial annoyance on normal, can be deadly very easily. Anything one on one is easy tbh as long as you know how to dodge and Quen.The shield sign makes this easy (Quen)
Machiavelli- I also took a while to get up the mental fortitude to start such a dauntingly huge game (I reckon it was 18 months after buying it I actually played it for more than 15 minutes), it was a bit overwhelming at first and I just found reasons to delay. My wife ended up completing it and I eventually decided to give it a proper go and it's honestly the best game I've played this gen and you honestly could spend an entire year playing nothing but the one game tbh, it's that big. The plot is great, the characters are great, there is so much to do, the world is vast, beautiful and full of things to do, Gwent is horrendously addictive and the combat is spot on. It's pretty much perfect tbh, barring the slightly long loading times when you die