It simplifies your gameplay. You should try it, but a good two bar build will ultimately outperform it and needn't be super complex on a templar either. Templar has good situational skills, except Oakensoul limits your bar space. Especially in PvP I find Oakensoul limiting for that reason. As mythics go, Velothi-Ur is another option that works well on templar. It simplifies your gameplay in a different way, e.g. it eliminates the need for good light-attack weaving.

As a level 13 you don't need to concern yourself with build-crafting yet. If you enjoy questing, those are so easy you may well have the most fun if you remain ignorant of combat and only explore that topic gradually. This may leave quests a tiny bit challenging and, thereby, more immersive.

If you are an experienced MMO player, then the preview of where magplar stands in endgame is as follows:

• Excellent for solo play. Historically one of the "easy mode" classes, it is nowadays pipped to the post by arcanist in that regard. That said, I'm a 9 year veteran and I still enjoy templar despite it's easy mode / beginner tag, and despite arcanists existing, because it has a complete situational class toolkit, including execute, gap closer, and purge.
• You could limit yourself to two skills, Puncturing Sweeps and Radiant Glory. You self-heal from both. Maybe add an emergency heal in Honor the Dead, and that's basically it. If you want to keep things that simple for now, Oakensoul would suit. Note that Radiant Glory / Oppression, the execute, is templar's standout damage skill these days. If you have a longer fight against a high health boss, you should start beaming them with that skill from 40% of boss health. This is where templar gets most of their damage from in endgame, these days. Even arcanist can't compete in the execute phase.
• Templars make good damage dealers in endgame. They can be the outright best in some fights.
• Templars are also the original healer class. They still make good healers, even if wardens have aguably become standard and nightblades are, weirdly, also used.
• While every class can also tank, templars are usually not used for that in endgame. Endgame, e.g. 12-person trials, revolves around the unique buffs, typically damage buffs, that characters can bring to the whole group in ESO. Templars fall short in that department, when used as a tank. Everything is viable, but they are not best in slot for endgame tanking.
• In PvP solo play, templars are currently not in a good spot. They can be tanky, but they don't have enough damage, other than with their execute. You can compensate by completely switching away from your PvE playstyle, but still expect to be beaten by equally skilled players on another class. In group play, however, the execute is super nasty. TL;DR: Play in a group.