Well?

Just been to the Stafford Classic Show and a lot of the bikes of the time were running without filters and just used...velocity stacks? (I'm not sure of their name-funnels attached directly to the carbs)
What are the pro's and con's of this set-up? I realise it's to maximise airflow but what would be the worse that could happen if, for example, I did it to my bike? And, if it would mess up my bike, why not the older bikes? More tolerant carbs?

As an aside, saw a 62 Beezer Gold Star...and fell deeply and madly in luv. Nothing superfluous, just the essentials to do the job in hand. It was immaculate, too; it made my bike (07) look old and knackered! Anyone got a spare 13k quid to lend me?!! Anyone?!