I love sequencers, I love Nerdseq. Everyone else is doing a great job explicating it, so I'll be brief:
Nerdseq can do intricately programmed music/ cv modulation etc. on par with a DAW, but when I play modular I am not interested in just pressing play on a composition, I want to be able to improvise and genuinely 'play' the instrument. SO, after years of testing many different sequencers, I've settled on a suitcase rack with a performer, and a suitcase rack with a nerdseq. The performer is very immediate obviously, and the Nerdseq is as well, but it took me longer to get to the point where I could real-time jam on it.
For me, the biggest hurdle with getting fast on the Nerdseq was simply the screen.
1. There are a lot of numbers, so it takes concentration to decipher quickly, and 2. It's in hex, so you have to be ok with that.
It took time for me to get comfortable with it, at first it gave me eye fatigue from staring deeply, trying to figure out what's going on. Two years in, I feel like I can start from scratch, and just play a show, boom. Love elektron sequencers and many others also, but to me, it's the holy grail!
PS. I understand anyone frustrated by it, literally every sequencer has advantages/disadvantages, and I get how annoying it can be to look at a moving screen covered in numbers. uggh