Yes. I think that is ludicrous. And anyone else who knew you had a $100,000 car in the garage but drove a 1980 Holden Camira ($5000 worth) everyday would also think that you're nuts.
I wouldn't buy a $100k mercedes to "show it off". I'd buy one for the driving pleasure it gave me. The comfortable interior, the creature comforts, GPS sat nav, heated seats, premium nappa leather, etc etc. All these things are there to make my 10 minute drive to the station more enjoyable.
Please don't get me wrong. I'm in no way opposed to buying a second car for daily commuting duties and shopping centre trips. But if you spend all your money on one super duper amazing-mobile that you end up being so scared to take it out into the big bad world, and then have to resort to using a $5000 crapper instead, that my friend, is absurd.