If students from abroad get the right to vote it sounds indeed like a good idea to make it possible to vote in the place where they are studying.
Otherwise, two things could happen. The first one is that only students who can afford to come back for the elections get the opportunity to cast their vote.
The second possibility is of a darker nature: politicians could pay students to come back on the condition that they vote a certain way.
Similar things have happened in the past, for instance in Greece where the ruling socialist party once offered plane tickets to Greek voters from Germany. Those voters came home in droves, but when they wanted to return to Germany after the elections they found out that the party had bamboozled them with a one-way ticket and that they had to pay their return fare themselves.
Such wickedness we can do without here.
Source: Today SXM Editorial: Two things