I have found value in putting references to any source I can find that is reasonably accessible to the masses. While I know the simple act of creating an account on FamilySearch often prevents some individuals from accessing those records, because it is a Free account, I don't regard this as a significant obstacle. So I try to maintain a primary source record set with any references to FS as possible - even if they are duplicates or a secondary index to the same original. I often find that different indexers see different things in the records they index, and those clues often help me find the next step in the journey.
However, there are certain records that can only be found beyond the magic paywall, so if I can't find a comparable record on this side of the paywall, I will reluctantly put references to those records so that it is clear where the data came from. I don't put duplicate references where a free site citation already exists, even though that might prove helpful in the future. I do have "temporary" access to Ancestry for now (for example - there are numerous other pay sites), but I would venture to say I'll lose it in the future and those links will become inaccessible to me. So it will only help me in the future if I link to as many non-pay site sources as possible and not duplicate them with additional pay site matches.
But that's just my approach - I'm sure it's different for many others. I've often seen the approach of only putting one citation per original source, which is fine. I've also seen some who will only put Census information. That's helpful, but it only documents certain key historical pieces of data, and things like exact birth or death get missed in the process. Often I'm just glad there's at least One citation on the source list, but I suppose that's now delving off-topic and I'll stop now.