Yes, I do and have had for a long time. I keep the ap on my phone, and check it every few days, to ensure that there is nothing on there that is incorrect. Have found them very helpful on several occasions when I have had problems with something I have ordered/paid for and not received, etc. They have always dealt with that speedily.
You must have been saving those rewards for a very long time to reach that amount. I usually take mine out whenever it reaches about £20 - and they are not very generous.
Of course, this year have used this card more than usual, as so many places prefer card payment to cash. I do keep a small cash book, in which I write down every time I make a payment with this card, so I can keep a running total of what I will be paying them next month. Always paid in full each month via a DD. I understand that the interest rate for those that do not do this is very high.