As the Clone Wars broke out across the Galaxy and the Jedi were forced to take up combat roles as Generals leading Clone Troopers, many of the Jedi looked down upon their men and had little respect for them. Obi-Wan Kenobi, along with a few others however were notable exceptions to this, showing tremendous respect to his troopers and forming strong bonds with them, despite them being bred for wear… So, lets break down the heartwarming reason that Obi-Wan Kenobi chose to wear Clone Trooper armor during battle, despite not needing it!….
So the first major reason is pretty obvious and that was for defensive purposes. As you can imagine, the standard Jedi robes provided at the temple of Coruscant aren’t going to do anything against the rapid blaster bolts coming from Battle droids…. Obi-Wan, unlike many younger Jedi, understood that although he was a proficient defensive Jedi and that he was most likely able to defend himself from anything that came his way, with just his saber and the force, he never got too confident or complacent.
Obi-Wan Kenobi was an absolute master at Form III lightsaber combat, known as Soresu, which relied heavily on defensive movements and had the aim of essentially outlasting an opponent, waiting until they made mistakes… which was quite quickly for most battle droid models. Because the technique utilized tight moves, subtle dodges and efficient parries, it quickly became the most defensive of the main lightsaber forms recognized by the Jedi council. Although Obi-Wan absolutely perfected this highly defensive lightsaber Form, he never forgot his Jedi teachings and did not get too confident in his abilities. He knew he wasn’t invincible and that one momentary lapse in judgement could kill him, therefore he took extra precautions like wearing Clone Trooper armor alongside his Jedi attire.
Furthermore, he knew that once the Clone wars started and he had seen the first waves of Battle Droids land on contested worlds that he was going to be facing such a huge amount of blaster bolts, that it would be stupid of him to think he was not going to be hit… Even believing it would be arrogant and prideful of him to think that way, something which he knew went against his jedi beliefs.
Now following that, we have the really heartwarming part of why he incorporated Clone Trooper armor into his Jedi attire, which is that he wanted to show solidarity to his Clone Troopers. While many Clone Troopers were forced to report to horrendous leaders like Pong Krell or the plain hateful Quinlan Vos, Kenobi did not want his men to face that disrespect. He did everything he could to make his troopers feel welcomed under his command, and that included wearing a piece of their armor, to symbolize his friendship with them in battle.