It avoids the "causal" N=1 accusations on social media while not being
as expensive as literally paying people to experiment or having
institutional review boards. It is simply not pragmatic for ordinary people who
want to do investigations that rich organizations find too insignificant
to attempt.
Surveys are like a good example, e.g., to reach a majority consensus on
a non-objective topic.
Honestly I think even with actual science, the sample would inevitably
have a sampling bias that only people who volunteered
will be tested (otherwise it is an illegal waste of their time).