Going through with the impeachment trial is not pointless. In addition to removal from office, an impeachment conviction also comes with the opportunity for a separate (Senate) vote to ban the person from ever holding public office again. We need that.https://www.rd.com/list/things-people-get-wrong-about-impeachment/ …
As far as the question of whether Trump will lose the perks that come with being a former president (pension, staff, office, Secret Service protection, etc) that too is up in the air. [The article earlier in the thread explains why.]