Besides looking hideous and completely ruining resale value?
Do you have any evidence of it hurting resale value? Seems with the modding done to Jeeps one could really argue that point on any specific mod. It's subjective anyways. Resale is what one person thinks your Jeep is worth. You might find a buyer who loves the look and is willing to pay.
I think instead of ruining resale value, it narrows down the amount of people your jeep will appeal to. I have seen a few lined Jeeps for sale in ads close to where I live and either they are there a long time or they end up selling them super cheap.... so yeah it does ruin resale value as well as narrow the amount of people looking.
Been jeeping for years, bought and sold many jeeps, viewed and followed many more.
The market for a 'bed-lined exterior' anything is significantly less than standard paint.
Sure, you may find that 1 person who has the same taste as you, but you likely turn off 100 others who do not.
Some buyers may buy a jeep with a color they don't care for thinking they may change it down the road, but very few are likey to want to remove a lining to do so, and I don't think you can paint over them with any decent results.
They are harder to clean (completely) than paint and still can/will scratch, as well as fade.
Nothing personal to you or your tastes, but I would NEVER recommend it as an option
Seems like it might be better to attack yourself at that cost. The looks will become pretty subjective with a bedlined exterior anyways, it will probably be a love it or hate it look. I doubt anyone would notice some slight imperfections as it'll already stand out