So this review is difficult because I bought this thinking I would use it to either slow cook or cover our food while it is sitting. I don't do either. But this product is well made and fits. It also has a small steam release hole in the lid which releases enough steam to keep it from bouncing around from steam build up.
SLOW COOKING (NO): My IP doesn't slow cook well at all. Actually, the slow cooking is so slow that it probably takes about half again as much time as when I had a slow cooker (which I got rid of because of the IP). But this is not a problem because I no longer slow cook. I've done it twice since I bought the IP, which was nine months ago, because slow cooking is for people to thaw things out and plan ahead. Not this gal.
COVERING IP WHILE WAITING (NO): I use the regular pressure lid for this because it keeps the heat in excellently. If you want to keep your food hot while waiting, use the regular lid. It is more insulated and sealed and therefore better for keeping the heat in your food. I never use the tempered glass lid to cover the food while waiting to eat.
COVERING LINER FOR SERVING (YES): I can see this for use if you are taking out your liner and you are serving out of the liner or just setting it aside and want to cover it. But I've never used it this way.
COVERING WHILE SAUTEEING (YES): I can see this for use if you need to sautee in your IP for a while or keeping something covered while keeping the heat on in the Instant Pot (I ALMOST used it this way, I turned the sautee back on, after I had thawed the spaghetti sauce I premade, and thought of covering it as I cooked off some of the water, but this was a bad use because I didn't want the water to go back into the pot, I wanted it to cook off).