Don't forget proper insurance if you're going to be using an old restored or restomod car as a daily driver. It should be a policy where the car is appraised and that value is accepted. Otherwise if some moron runs a red light and smashes into you their insurance will just give you the $500 book value for your "old car".

It can be a good idea depending on the car condition, price as well as the type of the car. 

A big factor can be parts availability - if you go out of town and your alternator or water pump goes out, will you be able to get the parts at the local parts stores? Is it common enough that mechanics know how to diagnose and fix problems? If it's pre-OBDII, diagnosing problems can be very difficult for a scanner-era mechanic, and many won't touch a carburetor.

That being said, I think if you were careful what you picked - like a Mustang or a Grand Marquis, a Toyota or a Mercedes, it could work out OK. But don't expect to do 20K miles a year with nothing but oil changes.

I also want to point out to the insurance topic as Chuck did. I don't drive my FJ Cruiser as a daily driver but still have it insured for its declared value and not the ridiculous book value the insurance company was suggesting. And keep in mind with valuable cars you'll be paying higher insurance too so you have to see if that is something you would want to do or not.

If money isn't an issue I would suggest going for one of those very nice older Land Cruisers or an FJ40 even; the second one has a very high value especially if restored if in mint condition. 

Are you passionate about getting dirty and rolling around under cars with bashed knuckles, and swearing at rusted bolts. Do you have a LOT of free time and need another hobby? Loads of extra money burning a hole in your pocket? If yes, then follow your burning desires.  You should already know the answer. Who are we to tell you how to live your life.

If you think you're going to get a cheap daily driver this way then you're mistaken. There's no free lunch.

It all depends on who you know, what you know, how much money you have to spend, and some luck. Daily driving one? You'd be nuts unless it's a couple miles down the road, or you've gone through everything.

Stay away from cars that people collect; Mustangs, Chargers, Challengers, Camaros... all are going to be way overpriced for their condition. You might get lucky and find a guy selling his toy for cheap due to a nasty divorce, but unlikely. People know they will get the money for a good start on those cars. They'll also try to charge a fortune for rotted out cars, hoping you won't notice until you sign the contract. 

Personally, I would go for a late 70s full size sedan or coupe. They're not really collector's items, YET. GM, Ford and Chrysler cars are your best bet. I paid $750 for my '79 Catalina last year from my girlfriend's dad, put $730 in brakes and tires on it, and it's now a fun toy. He was going to list it for $2000. If I fix the oil leak, I could possibly DD it. I dropped the original oil filler cap Friday night in the driveway and destroyed the gasket. I went to AutoZone down the road and got a new one the next morning for a 43 year old car. 

If you're not at least somewhat mechanically inclined and don't like hard work, sometimes doing the same thing multiple times, it's not the hobby for you.