In the end, AJ, if linen backing this and having the fold lines completely flattened is what you want, then certainly, it is an option for you, regardless of any added $ value or not. If the added value is how you will most enjoy it (and if you find the fold creases distracting) then it is an alternative not to be totally dismissed.
Backing a French 47x63 1P can be a little pricey, tho, so that is something to take into account.
AJ, there are so many 1960s, 1970s, and 1980s posters out there that have been linen-backed so don't discount it.
Linen-backing a post-1960 poster IS sometimes necessary and DOES add value to the poster.
Even folded posters that are in pristine condition can go for more money linen-backed than those that are not and there are a number of reasons for this.
Just don't bother with post-1990s posters that have been linen-backed - this is when it causes a problem as posters from this time period really don't need it.
My mate had a 1962 Dr. No UK quad, bought it for £760.00, sent it for linen-backing and sold it for £4,500.00 - yes, it's an extreme example but you get the idea. There are others like this too. In my own experience, I sold a folded 1982 Blade Runner one sheet for only £70.00 once...in the same sale I sold a linen-backed version for £205.00 - both same condition (the linen-backed one had simply been linen-backed, no restoration or fold line touch up or anything). I also have a James Bond poster I paid less than £500.00 for, getting linen-backed at the moment, which I know will be worth in excess of £1500.00 when it is completed.
Some posters rightly so are not worth the trouble of linen-backing unless you really like it and want to do it for no other reason than to enjoy it. I have a Disney poster for instance that is worth less than the cost of linen-backing alone, but it is a very nice display piece and once completed I will be framing it for my Mother as she is a Mickey Mouse fan.
Linen-backing your poster, I believe, would not add anything to its value; conversely it wouldn't take any away either.