You can attach trailer to bicycle and use it to transport your kids to nursery/school during winter. There I live both things would be illegal with motorcycle.
Total bike and trailer builder and believer of yore here.
One can fail to appreciate the additional breaking forces
and shifts in balance a loaded trailer introduces to the bicycle.
Where the trailer attaches should be as close to the center of gravity of the bike & rider as possible so the trailer's resultant forces have the least leverage.
The trailer hitch should be rotationaly neutral which is a gentler way of saying
if the trailer flips over it should not take the bike down with it.
If the trailer has its own breaks they should slightly and lightly lead the bikes rear break.
Being careful helps, I never wrecked, but do see how the addition of electrical assist does up the concern as it could result in more mass moving fast.
I've been rear-ended by other drivers a couple of times, once in the centre of town. If a child in a trailer been between the two vehicles they would have been killed. The reason for one of the rear-endings was that the brake rubber came of the pedal. I don't trust other drivers to not be on their phone or to properly maintain attention at all times. The OP also said that he did this in winter time. Here in the UK there can be black ice on the road at that time of the year.
