yes, but for many years, they are. They test if composite armor is viable, if buyoncy and other ship gameplay things are okay, how submarine mechanics could work, how a modern UI could be, if tacticle ground battles are an option, how viable are xyz things.
Yes, at least many of them had a funny twist (even the pirates one) and one of the “new gamemodes” is definitely more a funny one (like the recurring tail spin), but generally now there are also used to test some idea/mechanic they want to try out.