I personally will Not leave home without them. I've never had a problem cashing them. Sometimes when I am off site, I may be asked for i.d, but this problem can be solved by cashing what ever you think you will need at the front desk. A few years ago, fresh off the plane, and I lost my travelers cheques. What a way to start a vacation! Anyway, I called American Express, and I had new TC in my posession by 9:30 the next morning. Service was great, and I highly recomend them.
I have never used the new TC card, but I really don't care for the idea. It reminds me too much of a gift card. I like to count my money, and TC at the end of the day, and budget accordingly. I don't think I could do that with a TC card.