It seems like it doesn't cover much of anything for this list:
WHAT IS NOT COVERED
The BMW Certified Pre-Owned Protection Plan and the BMW Certified Elite Protection Plan provide specific
coverage against defects in materials and workmanship. There are various items that are not covered by these
warranties for enrolled vehicles retailed on or after January 1, 2014.
Brake pads and rotors (discs), brake shoes and drums; filters; fluid replacement of a component by itself;
scheduled maintenance services; spark plugs; wiper blade inserts, blade assemblies/beams.
Adjustments; batteries (as a stand-alone repair); driveshaft flex disc (guibo coupling); engine drive belts; exhaust
systems (including the gasoline engine catalytic converters, and the diesel engine “SCR” catalytic converter and
particulate filter); flywheel, ring gear and clutch disc contact area; fuses; manual and “SMG” transmission clutch
assemblies; oils, lubricants, fluids, refrigerants and coolant (except as required in the course of performing a
covered repair); rubber engine and heater coolant hoses, vacuum hoses (including clamps and connectors); tires;
tire balancing and rotation; wheel alignment.
Ball joints; bushings; center tie rod; coil springs – sagging (except for leveling system pneumatic/hydraulic springs);
control arms and brackets; idler and pitman arms; stabilizer bar links and supports; strut elements/shock absorbers
(dampers); tie rod ends and adjusting sleeves; trailing arms, thrust struts; wishbones.
Air leaks; body carriers, cross members, supports, braces and mounts; body panels, body shell, walls, partitions
and chassis sheet metal; body noises, squeaks and rattles; body seals and gaskets; bulbs - incandescent, Xenon
and LEDs; convertible top (except for electrical/electronic components); damage due to rust, corrosion or
contamination; door brakes and checks; door handles and carriers (except for electrical/electronic components);
exterior moulding, trim and fasteners; gas pressurized springs/struts; glass - side, sliding roof, rear and mirrors
(except for electrical/electronic components); latch and lock mechanisms and their related components (except for
electrical/electronic components); paint finish; water leaks; wheels and valve stems (except for electrical/electronic
components); windscreen (including the sliding roof); windshield (except for the front rain sensor); wind noises.
Bulbs – incandescent and LEDs (except for the instrument cluster); carpeting; floor and trunk mats;
headliner/sliding roof liner panel; interior noises, squeaks and rattles; interior dashboards, consoles, panels, covers,
vents, grills, trims and fasteners (except cup holders); seatbelt extender arm assembly (except for
electrical/electronic components); sunblinds (except for electrical/electronic components); sun visors (except for
electrical/electronic components); upholstery (except for seat heating elements and seat occupancy sensor mat).
Accessories (Standard and Optional)
All non-original equipment parts, components and accessories.
Especially if to add a 6th year is $2,500 dollars....
It seems like the better idea may be to just get a used i3 with a clean carfax history and holding the difference between that and the CPO for future repairs?