Nope. Bullet does not require spatials. JME wraps some Bullet stuff for you but that's really doing 90% of the stuff you expect the ES to do for you anyway. Bullet in an ES is using only RigidBodies and you ditch the spatials.
This is important because just because you use a 50,000 triangle mesh in the scene graph does not mean that you are using a 50,000 triangle mesh in the physics engine. These two things are completely separate. The model system will load appropriate spatials for the "model info" component. The physics system will load appropriate collision shapes/meshes for the "model info". These may occasionally be the same thing but quite often not.
I'd argue the same for ray casts. Ray casting into a scene meant for visualization is not always a very good idea... unless it's supposed to be purely camera-based style ray casting... like even that pixel in that leaf texture should clip the ray.
Separate all of this into different concerns.
You have a WalkSystem. The WalkSystem watches all entities that have Position and WalkSpeed. Once a frame it moves these entities.
Some other buff system watches for all entities with a Buff component. The Buff component has a target pointing to the entity to which it applies. Every frame, the buff system goes through all of the current buff entities and accumulates total buffs per target entity. (You may have many speed buffs at once, after all... plus slow buffs, and so on.) At the end of this loop, it goes through all of the target entities and applies the collected buffs, in this case WalkSpeed. That's it. That's all it does.
There is another DecaySystem that watches for any entity with a Decay component and removes it after a certain amount of time. That's it. That's all it does.
If you want to have a temporary buff then you create a buff entity that has a decay component.
If you want your buffable mob to have a default walk speed then you create a 'permanent' buff for it... which is just a buff entity without a Decay component.
That's it. You have three separate systems that do very specific jobs, are otherwise unaware of each other, and can be combined in a bunch of different ways.
Area of effect buffs are similar. A system that detects if an entity has entered some area and creates buff entities on it. When it leaves the area, it removes them again (or they auto-decay and you do a little book-keeping to keep them refreshed or whatever).
Simple systems doing simple jobs. Reusable.