Re sale value means nothing to me and I never purchased any release thinking it's going to be an investment
I purchase to have in my collection and I open every release I get to enjoy all the contents inside and outside
I have never sold any of my collection
I keep the majority of them some I give away if another release has better extras or picture quality in terms of the Blu-ray Disc
To me purchasing for resale is not a collector because once you sell it you no longer have it in your collection
Well what I can add is that it be nice to know what you purchase won't be worth peanuts in the short run so you have some or at least a little reassurance that there is some equity in their value. This hobby is by no means cheap due to the influx of releases. 10 premium steels can easily hit £400 - £500. 10 standard steels £200.
Let's not get confused with 'Buy to open and enjoy' vs Retention Value (and don't confuse this with Re-selling for financial third party gain).
You cannot predict the future, and for whatever reason you may want to offload them. Whether you are bored with your collection, you lost interest, financial problems, the movie was crap, or to help fund for the next release, sell to make some profit because you been a victim of a scalper, it can be any reason.
Steelbooks that are cheap, £5-£7 local standard releases then it makes more sense apply the 'Buy to open, enjoy, and don't care about the value etc, etc'. Simply because they are cheap, there is little harm done to your financial budget.
But now the market is much more directed to the Premium releases to give this hobby some life and an optimism to continue to collect, it has become so much more expensive. £40 - £50 now raises a few eye brows where you need to be cautions with your spending. 4 Premiums easily can hit around £200. So I would definitely consider the Retention Value if I am investing that amount of money for movies in a collectible packaging.
If this hobby is cheap then most would not really care much about the value. I've got like 500 Blu-rays that I paid £5 - £10 and now worth peanuts, average of £2. It does not bother me because I expect these aamrays to depreciate value and eventually be worth nothing. They are not limited, and therefore not a collectible item.
We get confused here thinking that steelbooks should not be treated as an investment.
100 steelbooks averaged at £20 = £2,000.
200 steelbooks = £4,000
300 steelbooks = £6,000
That's a lot of money to not have a consideration for it's value. You can buy a sideshow statue for £500 and for whatever reason you needed to offload them it's nice to know the equity still exists in them and they don't go for peanuts. How is this any different with steelbooks? They are cheaper but more quantity. Statues more expensive but much less quantity. However you look at it, it all comes directly from our bank account that funds them. I don't see any difference.
So I would say for certain and mostly premium steelbooks retention value is important to me. The cheap local discounted releases are different.