Seems (to me) the only hindrance to bringing a bike in the house is a spouse who says "No", or not enough space. If you live in an apartment and take the elevator, Tern (AIR) has a cargo bike that can be lifted vertically. Also with almost any DIY system, the batteries are removable (but should only be kept and charged where you wouldn't mind having a fire IMO). Doubt anything will change with battery chemistry in the near future (and even if it does, the systems could be more temperature-sensitive).