Difference between Campaign standard and classic? Both have same features?
If you have limited marketing needs and/or a strong dependency on realtime access to Adobe's new CDP, Standard would work best.
Classic has many more features and capabilities, essentially infinite given its open design, though requires technically proficient implementers and users.
Classic is a product run as client-server distributed software. you need to install a thin client to access it. You can also install it on premise.
Standard is web based, accessed through browser, and hosted at Adobe end generally.