Yep! For me it's a good £300 cheaper a year for me.
So it’s cheaper to buy a ticket with a railcard then a season ticket
No, but it works out better for me to buy daily tickets with the 16-25 railcard.
The Two Together railcard gives better discounts, and can pay for itself in one journey. Not very flexible though, as you have to travel with the same person to get the discount (and both of your photos are on the card). Good if you are touring round the country looking at universities.