Should Le Creuset only be used as display ???

SIGNATURE BUFFET CASSEROLE: COASTAL BLUE

So I brought a signature buffet casserole in 2012.

After about 4 years I started noticing a yellowish colour on the Casserole lid, this means that the gloss enamel is fading. I took the item back to Tygervalley store, they told me the Casserole is just dirty and they cleaned it. After receiving this back, I was still not happy but had to leave the situation as is. Knowing at the back of my mind, that I had my mothers round casserole exchanged for a brand new one in Windhoek, Namibia.

3 years later, the Casserole being 7 years old now, I again explained to the Tygervalley store my situation. They said I should bring the Casserole in for a formal assessment.

At the store, they all said that the Casserole is just not clean enough. They did ask me all the questions about using the dishwasher, on what heat are you using the casserole, blah blah blah. I did explain that this Casserole have never been in my dishwasher, and I use it on a gas hob, and mostly in the oven. I only use my Casserole on the Glas hob once out of 10 uses. There responds was that they will have it properly cleaned and all the marks will be gone.

After a 6 day assessment, I did collect my Casserole yesterday (31 Jan 2019). The Casserole still has all the marks as before the cleaning. The lady at the store even grabbed a sponge with some cleaning chemical just to check that is was cleaned. So I'm not really convinced that my Casserole actually left the Tygervalley store for a formal assessment. You can see on the one photo, the person that was supposed to be cleaning the Item, did not even un*****ed the lid handle.

My two questions are:

1. Is this how a Le Creuset product will fade in time? You do give a lifetime warranty, but I really don't see what the point is. In South Africa, the Casserole's cannot be recoated. So the lifetime warranty does not mean anything here. So my verdict out of this whole experience is not to buy any Le Creuset items anymore, cause I can rather buy a brand new, cheaper product every 2 years, instead of a very expensive Le Creuset that will start fading in a few years.

2. Or should you actually use your Le Creuset Item as a DISPLAY unit just for show? Is this the only way to keep the product in pristine condition?