As one of the last generations of sailing ships, windjammers were much larger than their older counterparts. As such, there was much more space for staterooms (small though they are) and lots of cargo.
Rich passengers, which she carried in her life as the Euterpe, got much smaller living spaces, but still pretty reasonable compared to earlier ships. Less well-heeled folks got berths down below (which you'll see later).
The steel hull was stronger and thinner than wood, allowing for more space for cargo, passengers, or whatever owners wanted. Also, check out the Cutty Sark, built a few years later. A different design of ship, but a similar hull construction.
As the Euterpe, she was a "full-rigged" ship, but when she was bought and renamed Star of India, her aftmost mast was converted so she became a barque. Apparently that reduces the crew requirements, along with some other advantages.
The San Salvador is an interesting replica. Where the HMS Surprise could pass for an old ship, San Salvador feels new. OK, it is new -- it just opened for tours last year. But it also has a lot of materials that seem anachronistic.
The Berkeley was in service for 50 years, ferrying thousands of passengers between Oakland and San Francisco. I can only imagine that while her design is historically beautiful today, in the mid-1950s it must have looked exceptionally dated.
The San Diego Maritime Museum's best aspect is its variety. Sailing ships, submarines and a historic ferry. I recommend spending a day by combining this museum and the fantastic USS Midway museum, which is just a few minutes walk away.