Not that these low-level contributions aren't important. They definitely are. But if these were the only contributions that everyone made to online trees, our knowledge about our ancestors would progress much more slowly. High-level contributions, on the other hand, tend to be harder-won. They're widely copied, but much more rarely offered firsthand. I'm going to coin an acronym here for them for the purposes of simple reference and rhetorical punch: NPC's. In the video gaming world, "NPC" is short for "non-player character," which means any character in a game controlled by the computer and not by an actual human playing the game. My acronym, though, will stand for "Non-Pajama Contribution." Why? Because the high-level contributions I'm talking about require one to get up, get dressed, leave the house, and go seek the valuable sources that are inaccessible on the internet. (Or, they require you to get in contact with someone in close proximity to needed resources and is willing to send the records to you, sometimes for a price.) A high-level contribution, or non-pajama contribution (NPC), is a source that hadn't been digitized and wasn't widely accessible on the internet prior to the researcher putting it there. NPC's often dramatically advance our knowledge of the people with which they're directly concerned. NPC's, provided they're cited and vetted properly, distinguish those who make them as special facilitators of new historical discoveries. The stuff of NPC's is typically found at libraries, archives, courthouses, county clerk offices, and personal/inherited collections, among other places.
Here's an example:
Say there's a shared ancestor that Ancestry's or FamilySearch's record indexes only say died in 1886. The FamilySearch Family Tree and just about every public user tree on Ancestry has duly copied this fact. Then YOU, as the Non-Pajama Researcher, get curious enough to visit the repository where a death record for this person is held. You might pay a fee for the document and/or image. Then you post the image to the FSFT and your Ancestry tree, along with a full citation describing the source and when/where you got it. Boom, this is an NPC! You are now responsible for authoritatively demonstrating that this person died on August 23rd, 1886 in Pittsburgh, PA. You've put something valuable on the internet and have advanced knowledge of your ancestors.
For another example, here's an NPC record I found:
This my great great uncle's declaration of intention to become a naturalized U.S. citizen. It's not a large record that reveals a great deal, but since the origins of Mr. William Levithure (spelled variously) are a bit obscure, every bit of information from contemporaneous sources helps. For this, I had to travel to the indicated county clerk's office and dig through some very old tomes that were in rather delicate condition. Who knows how soon (if at all) this record would ever have been digitized and added to one of the major vendors' online collections? More records are being put online every day, but this is still very much true. Well, now the above record is online for people to see and use...because I put it there.
I can understand not wanting others to "get a free ride" off of one's own hard work. I used to think squarely this way. But I've come around to a different mindset recently. I'll tell you why. Most if not all of us have been the beneficiaries of records and artifacts as a result of the generosity of older family members and other researchers. Often the only thing they ask in return is to be good stewards of their history, preserving it for future generations. Increasingly, my eye is on eternity when it comes to genealogy. What's more important in the long run: that I didn't give others a genealogical free lunch, or that I did what I could to preserve my family's memories? I think the latter is more important, and the best way to do it is to make as many NPCs to online trees as we can, and cited as meticulously as possible.
So, by all means click and work through those Ancestry/FamilySearch/Etc. hints. They're great, and they'll increase as the terrific people who digitize these sites' collections continue in their important work. But if that's all you're doing, and you're capable of doing more, you're limiting yourself and anyone else who might benefit from your high-level contributions. I invite you to maximize your research, get away from your computer, and seek the higher-hanging fruit where it may be found. Digitize and share whatever is physically and legally possible. The people researching your lines will thenceforth bless your name.
(3/13/2020 Edit: Obviously I am making this argument with the assumption of normal conditions. At present, it's best to take precautions suitable for helping to slow the spread of Coronavirus [COVID-19].)