BritRail England Passes compared to return ticket for travel in England

Yes, the pass is much cheaper than buying all the tickets you may need individually, and in many cases a pass allowing unlimited travel on any 3 days in 30 is cheaper than one single ticket you might intend to buy. Especially if you use the free accompanying child pass. (You can also get a pass for an accompanying Briton if you're visiting someone and then traveling around with them.)

What's more, with the pass you don't need to book a specific time and worry about missing your train. And the premium for 1st class is less than the premium on individual tickets.

The only downsides (I've used these passes, mostly London Plus, for 5 years or more once or twice a year) are that you can't go through automated ticket barriers, but have to find an attended one where you can show the pass (or, in my experience, the cover/envelope it comes in) to an attendant, and you can't book a specific seat. I get 1st class passes and have never had a problem finding an unbooked seat to sit in. You also have to order it while you're still at home and have it delivered to your non-British address, so you need to plan in advance. And you'll need to line up at the first train station you reach to get it validated. These are very minor drawbacks.