You can make beers that are all of one malt to showcase those and/or learn what they bring to the beer. You can make all Pilsner, or all Maris Otter, or all Golden Promise, or all Vienna, or all Munich beers. I think I have done all of those over the years.
If you add Crystal, you no longer have a single malt. If you want to see what it does to a beer, you could make one that is 90% base malt and 10% Crystal C60. A beer that is 100% base malt would be your control sample. Make both and compare. If the 100% base is not too you liking, you can blend the 2 beers.
To see what different Crystal malts are like, you can either chew them, or do a small steep of crushed malt in 155F water at the ratio of 1.5 quarts of water to 1 pound of grain (scale that down so you don't have to use a full pound).