Tim,
These are questions based on what you've seen from both sites. And if you were doing a pretend or trial job search inquiry yourself. I would suggest looking up an ideal role that you would like and look them up on both sites.
Compare what they say, offer, provide about the role, company, insights, etc. Compare whats different? Whats the same?
Downsides of searching for a job online. Can be a lot depending on the perspective, your age, type of role you want, location, experience level or lack thereof, education, training, etc.
Downsides can include: lack of tech knowledge, no computer, no laptop, unsure of where to look, what sites are reputable, lack of communication or open post when jobs are no longer available, applying without ever hearing back, applying and never getting a response (normal), applying to a role where there is a lot of competition and it is hard to stand out (this is where a networking connection inside the company or someone you know that works at a place you are interested in can help), nothing available, you don't have the right skills to fit but want to apply.
All the best

Kim F.
12/10/20
Tim A.
you can do a pretend role12/10/20