One's age is concomitant with deterioration and pathology in organs that heretofore worked perfectly well and were healthy. As one example, everyone's heart substrate develops rogue signaling cells that, when they are sufficiently numerous, will work in concert to take over the heart's rhythm. This is why approximately 10% of all aged adults develop an arrhythmia or some other cardiomyopathy. But when you add in the typical onset of age-related comorbidities of all types, heart, lungs, kidneys, liver, vascular system, etc, they can all add up to put a person at high risk for thromboembolic events. Throw in the propensity to sit a lot more, especially if mobility is an issue, now we can add a risk of deep vein thrombosis. A little prophylaxis goes a long way. That's why aspirin was recommended for so many years, and still is. It doesn't mean that a DOAC should be taken instead, but if one can afford it and tolerate it, it does a better job than aspirin will. So, it's a matter of being informed, including about one's overall risk for strokes related to clot formation and travel. From there, it's a personal choice. For me, with a heart already disordered, but otherwise strong and clean of significant deposits, I choose to take a DOAC.
https://ashpublications.org/blood/article/130/Supplement%201/3720/71760/The-Safety-of-Aspirin-Vs-Direct-Oral