The Heki does have a blackout shade built in, if you want to sleep late. It also has a mosquito screen built in.
The problem with them is they are molded from thin ABS plastic. Treated very carefully and kept out of the sun (!) they work OK. The plastic hinges and latches are not robust to start with, and get embrittled by the sun. I think this is the reason most of the European suppliers sell covers for them. Heki themselves say don't leave the inside shade closed in the sun as the unit will melt. These things come from and are primarily sold to Nordic countries where sun is an occasional novelty. They have never seen anything like Phoenix AZ except in the movies.
If you do have to replace one, get the crank up version rather than the bar operated one. The mechanism might be a little tougher, but the main reason is you can open and close the dome without opening the mosquito screen first, which lets all the little critters in.