Intrusive weeds or welcome guests?

These colorful flowers are considered weeds here in the bay area. Back east, where I'm from, one buys nasturtium seeds in packets and carefully plants them in one's well-tended garden. The neglected patch of ground in my backyard is overrun with them now, and I couldn't be happier. They sprout and climb and maneuver their way wherever there's some soil and some sun. When I moved to the bay area, almost 6 years ago, I noticed the wild looking gardens in Berkeley. Many plantings in various front yards don't looked very controlled, but have been allowed to "express themselves," it seems to me. The Berkeley campus may be quiet these days, but plant life is enjoying its own free speech movement.