What are the advantages of email clients/web?

[Handsome Recluse]

What are the advantages of both in terms of efficiency, security, bandwidth, convenience, ease of implementation for extra protections, etc.?

 

[HarborFront]

What are the advantages of both in terms of efficiency, security, bandwidth, convenience, ease of implementation for extra protections, etc.?

You can read some here

Webmail Or Email Client. Which Is Better? | RefuGeeks

Webmail vs desktop email client: which should you choose?

Email clients vs. webmail: Which is right for you?

Security difference between webmail access and desktop email client?

 

[shmu26]

with webmail, most of the time you will be viewing attachments on the web interface, rather than downloading to your computer. That protects you from one of the biggest attack vectors: email attachments.

if you don't need the advanced functions of Outlook, you probably don't need a desktop client, unless you want offline access to your mail.
Gmail offline goes back a month, so that helps a lot, and I think it covers starred messages even if they are older. So that might be enough for you.