When the SBB says that the 1-day travelpass makes an excellent gift, I believe they are assuming that the gift is for someone who is already in possession of a half-fare pass (which almost half the people living in CH have). If your parents are going to be here for more than just a couple of days then it may pay for them to get the one month half-fare card for 99 CHF, then get a 1-day travel pass. Alternatively, if you know where you want to go and you will not be travelling during peak times then you can often get very cheap tickets by using the
Click and Rail deal on the SBB website. Often, tickets are available for even cheaper than the normal half-fare price, but you don't even need a half-fare pass to use them.