I personally have a hard time designing without talking with team members, friends, or random bystanders about the work. I do make breakthroughs when I sit down for some good ideation by myself, but before moving forward, I have to talk to someone. At work, this is a meeting (although informal). Working by yourself it's easy to get spun out onto random tangents and think for hours about rabbitholes, that in reflection with someone else aren't that important.

Both solitary work and meetings have their place.

(I'm an intorvert, mostly.)