We recommend safewords for persons new to kink, those who do Top/bottom scenes and/or those in new relationships. Yet there is no blanket rule for BDSM as many would have you believe. You decide what role safewords play in how you do kink.
You absolutely do not need a safeword if you don’t want one, that is how personal autonomy works. If it’s a decision you have made because you prefer to use regular communication in your relationship and play, or if you enjoy playing without that ‘safety net’ of being able to stop the action, it’s up to you.
In some well-established relationships, people will choose to follow a consensual non-consent model, where the dominant has blanket consent. The people who engage in this style of relationship are usually well-established couples who know and trust each other well. This is a much different thing than the dominant you just met.
In the end, do what works for you. If you want to have a safeword for every scene, do that. If you want to use plain language, do that. If you want to enter into a CNC relationship with someone you trust and don’t want a safeword, do that. Just don’t let anyone pressure you one way or another.