Erasmus is not for gap years. Gap years are between leaving school and starting uni and are not part of studies. They are privately funded by the young person and their family. Not everyone does a gap year or can afford to do it unless it involves them doing paid work.
Erasmus is to help fund time spent abroad as part of studies whilst at uni, for example, a languages degree.
I am delighted that we will be rejoining Erasmus. About time too. We should never have left it. In fact, I'm not sure we were actually required to leave it when Brexshit happened. Were we not offered the opportunity to keep our membership of Erasmus? Then both Theresa May and Boris Johnson refused to even get consider it, like the twats that they both were.
The Turing scheme was utterly crap. My DD had to spend time on South America as part of her languages degree and got nothing from it.
Erasmus is now more global than it used to be. It's high time we rejoined.
I personally think that we should also be rejoining the EU if they would have us back, but hey, one step at a time I suppose.