Honestly if it is not a burden on your financial situation having both beginner sets in your Library is a great benefit.
First I would go with the dice. Yes there is an app for the phone, but that is not for everyone. I know a lot of people who prefer actually handling dice. If you have both boxes then you have dice for both players and a separate one for the GM. In a game like this with specialty dice it is sometimes easier for a group if the GM has a dice pool for players to use. So just considering the Dice it can be a big win.
Now the maps and tokens are another strong reason for getting both. You can re-purpose them for your sessions. As for alternate tokens you can use. Yes there is a variety of things you can use. Some are cheap and some are not really cheap. That really depends on you as the GM and the group on what you can ( afford to) and want to use.
Then there is the adventures. This is always something you can save and use with a new group. Adapt the story for an advanced group. Having them in your library is just another source you can tap just like the adventure ideas in the other supplement books.
Getting the beginner sets is really what benefits you. If it is a cost you can not do right now that is fine, there is no reason you to not pick them up later on. Have fun with them and use them to further expand your library of resources.