For some reason, being Transgender is something that few people who aren't Trans understand (though a fair number of people support us) A lot of cis people are very attached to their own gender (as are we, I suppose), so they can't really imagine a world in which someone would not want to be the gender they were assigned at birth.
For me, having other trans and nonbinary friends is important. It helps me feel more valid, real, and worthy of my identity. Cis people don't have that same level of understanding, as supportive as they may be. So I really do believe that having at least a few understanding individuals in your life is very gratifying.
It's one of the reasons I joined this forum!