I'm in the US and I'm doing a Skype interview for a school here that's toward the bottom of my list. I still want to see what they have to say, and leave the option open, but it wasn't worth the travel expenditures for me personally. I think it's certainly beneficial to go to in-person interviews, but I don't think it will necessarily make or break you for every single one. I would expect them to be understanding of your circumstances.
My experience is a little bit different since I'm here in the US, but I thought I'd share that you're not the only one and want to see the advice others give.