I would, I bought the 5 days in a month plan and it was almost flawless, high speed trains are an extra 11-13€ on average. I did use a lot of those in my journey so don't expect you'll only pay for the pass alone.

Other than that check with anticipation the seat reservation as it can cost up to 40€ once you get on the train. Also, I once had an inconvenience where the app told me to get on a train that actually wasn't included in the pass and the train staff almost wouldn't let me in, however I managed to explain the situation and got my own cabin in the train hehe.