The biggest reason is that it's a reaction to RF-ification. Starting back on 1.7.10, there was a big push for every mod to move over to RF. This eventually cumulated in RF being renamed FE and becoming part of the Forge API. This was good for cross-mod compatibility and came to dominate the space.

1.12.2 was peak RF. Before Create, you'd have to go all the way back to Rotarycraft or Electrical Age on 1.7.10 to find a tech mod that wasn't seeped in RF, and even then people sometimes used these mods solely for generating RF. The closest you could get on 1.12.2 was Better With Mods, the Better than Wolves spin-off. (To play the original Better than Wolves, you have to go all the way back to 1.5.2! It still receives updates, but I'm getting off track.) True, there was Industrialcraft, which used EU, but 1.12.2 saw it get displaced by Immersive Engineering, which was somewhat similar in function but used RF!

The problem with RF is that it's kinda boring. You make it, you move it, you store it, and you burn it. It's fine. It functions, but the power transfer isn't that interesting. You also had "magic blocks/multiblocks," which were powerful machines that were basically plug and play and didn't need much design to get working right.

So when Create showed up, it wiped all that away and used rotary power. No RF, no magic blocks. Here are the pieces, figure it out. Nothing like it had existed for several versions. On top of that, it had a vanilla-plus vibe, which people like. It's visually interesting, which people also like. Stuff like that gets r/feedthebeast's attention, which gets the packdevs and the YouTubers attention, which leads to modpacks and videos, which leads to attention over the whole modded Minecraft scene.

On top of that, it is a genuinely good mod. It is in everything, though, kind of like how Tinker's Construct was in everything for awhile. Eventually people burn out on it due to overexposure and the pendulum swings back. How many packs have Tinker's now? Plenty, I'm sure, but not like it once was.

Somehow Create feels very vannila-esque. No UI's, no 1 block does it all, creative freedom,... It's a nice change of pace between all the tech mods out there.

Because it doesn't give you everything on a silver platter. You actually have to engineer, thus, more creativity.

Same reason people like Immersive Engineering, I assume. I've never really liked either.

I enjoy the creativity of making the lines vs just plunking down a one block machine (or a multiblock that has relatively fixed desing). It extends the vanilla goldberg-esque machine making instead of replacing it.

I have very mixed feelings about it, tbh! It's an amazing mod, and I agree with the stuff other people are saying about the complexity it adds + what that does for the overall gameplay.

I also get really bored really fast when I'm trying to make something simple & I have to drill down through like 5 different layers of "simpler stuff I need to make the thing I actually want". It just adds SO MUCH to the game that I get overwhelmed, and that stops me from actually executing any creative ideas I have. The complexity is its greatest strength AND its greatest weakness, I guess.

Most mods also have documentation / onboarding that's just not robust enough for me. Create has decent in-game documentation, I think, but tbh I vastly prefer a really solid wiki to an okay tutorial. I can alt-tab to a web page, but I have to stop what I'm doing and go out of my way to access an in-game tutorial; for a mod as complicated as Create, that puts me off no matter how many times I try to learn.

I guess this answers the opposite of your question, but hey. I feel you!

I mean in sense of movement parts is amazing. Much more now with the trains.and the addons.

Like if you wanted to make stuff that moves and is cool to look at, currently in the recents Minecraft versions there wasn't much in terms of mods.

I tend to agree with you, but Create is very visually appealing. Since a significant chunk of the Minecraft world is YouTube driven it makes sense to gravitate towards mods that look good in a video.