Impeachment doesn’t lead to jail, if it did, trump already would have two sentences
Despite it being a while ago and they claiming they have evidence, so far nothing was presented showing Biden in bad light (his 50+ year old son is not him)
It is unlikely that this investigation will show up Biden doing anything legal in that matter. They are hoping to find something else (like it was with Clinton) and in any case also normalize impeachment and show impeaching trump doesn’t mean anything, because they impeached Biden.