“The ease of making a lining”
When you have a fabric, like the brocade, that ravels on the cut edge very easily, you will benefit from making a lining in your garment, especially on the bodice of the garment where you will have to fuss with armholes, gathers, and curves. A lining makes for a really smooth inside and actually can be LESS work than making facings for armholes, narrow hems, etc. See photo of how much the brocade ravels. I zigzagged the edges to stop the raveling so I could work with it easier. You will be able to keep the fabric intact while working with it.
I used the same pattern pieces I used to cut the bodice from the brocade to cut the lining pieces. Patterns that specify and accommodate a lining will give you instructions. But you can use a lining even if the pattern doesn’t specify it. Just use the same pattern pieces you used to cut out the bodice, to cut the lining pieces. Follow the pattern instructions to put the lining pieces together in the same way you put the bodice pieces together. Then put the lining and bodice together, right sides together, and sew along the armhole seams and the neck and center front seam together. Turn right side out. There is a trick to turning it inside out, and then sewing the side seams. I’d recommend finding a pattern that has a lining and seeing how they do it. Get the pattern either from Bungalow, or from Simplicity or McCalls or Butterick when they go on sale.