At this point, I fear it would be counterproductive to have a Senate trial. In five days, the president will no longer be in office. If he is tried after he is out of office, the Senate will have to suspend business at a time when the new administration is not yet fully set up, and foreign adversaries may see that as an opportunity to make mischief. With no urgency to have a rapid trial since Trump will already be gone, there will be much less justification for limiting due process to a minimum. The proceedings will be more drawn out than they should be.
More to the point, the high probability is that Trump would be acquitted.
As noted above, impeachment is meant to be very difficult. Here, beyond that, Republicans have been given at least four reasons to vote against conviction: (1) the profound constitutional question of whether a president already out of office may properly be tried (I am in the camp that says a removed official may be impeached, tried, and disqualified, but it is a disputed issue); (2) the afore-described manner in which the article of impeachment was poorly drafted and rashly adopted; (3) the lack of overwhelming consensus in the country that Trump should be convicted and disqualified; and (d) the blatant partisanship of the House impeachment proceedings, including the fact that the first impeachment was unserious and the current one lays the groundwork to seek disqualification of Republicans other than Trump under the Fourteenth Amendment.
Consequently, the main effects of a Senate impeachment trial would be to keep Trump in the limelight, playing the martyr, and then to enable him to claim vindication when he is acquitted. That would make him more likely to mount an audacious 2024 campaign. I don’t believe he could succeed in retaking the presidency, but he could be destructive of Republican and conservative prospects.