Can the Huawei MateBook X run After Effects smoothly?

From what I saw on the Internet, the pictures of the lid on B&H indicate that this is the older model. Which is not necessarily a bad thing.

I've never used it, but on paper it will run After Effects OK on the go. But the following aspects of it may limit performance, according to a PC World review:

But the Matebook X Pro also looks better on paper than in the real world, due to three technical limitations that you should know about. First, we discovered that the Matebook X Pro is subject to power limit throttling. This means the laptop's CPU will refrain from using its burst (overclocked) mode when all of its cores are being stressed, reducing its performance potential. Second, the GeForce MX150 GPU used within it is a special down-clocked model, which saves some power at the cost of some performance. Finally—and this is a special case that won’t affect many customers—its Thunderbolt port uses only half the lanes that it could, which will limit its utility if used with an external GPU or monitor.

The graphics and Thunderbolt lane limitations should not affect you if you'll use After Effects using just the built-in display, and not connecting external NVMe storage. If you plan to do those things, the newer MateBook X Pro (based on Intel Core i7-8565U), other newer PC laptops, or a MacBook Pro would have a full Thunderbolt implementation.

The "power limit throttling" affects any laptop this thin. When you render in After Effects and the temperatures of your maxed-out CPU cores get so high that the thin laptop's meager cooling system can't keep the heat down, the CPU will cut back on Turbo Boost until temperature drops, so you'll see a lower maximum processing speed, probably along with fan noise and a hot case.

16GB RAM is fine, although I don't like the shorter RAM preview I get on my 16GB laptop compared to my 32GB RAM desktop.

In short, it will run After Effects smoothly…until it hits the thermal and RAM limits of its design, then things will slow down. If your portable After Effects work is intensive enough that those limits would be a problem, get a thicker laptop with a better cooling system, and maybe 32GB RAM if you want to avoid re-rendering RAM preview frames.

I don't really know anything about this manufacturer or specific device, but on paper that looks like it'd probably be fine for AE, as long as you're not doing anything too crazy.

Are you specifically looking for something with a touchscreen? In general, gaming laptops are going to essentially be a good starting point for an off-the-shelf product, since they'll usually have beefed-up video cards.

This recent article has a lot of good information on system specs:
https://www.schoolofmotion.com/tutorials/after-effects-computer

You'll always be making some concessions for laptops/mobile use, of course.

I wanted to know if it could run everything smoothly.

That's a relative term and will depend as much on suitable settings and smart workflows as it does on hardware. There cannot be an "if you buy this, AE will fly" answer because quite simply AE can't be coerced to do certain things just based on juicy hardware. I would suggest you look up the gigazillion threads on "performance optimization" and similar topics you can finsd on this and other forums. Otherwise this laptop should be more than enough to get most AE stuff up to a certain complexity done, but again, you shouldn't expect AE to e.g. always be realtime or chew threw complex effects setups without any delays. That's just not how this stuff works.

Mylenium