Yes, there is a point.
To be clear, "opting out" merely stops the targeting of ads. It does not eliminate ads, or reduce them in number, or vastly reduce the more insidious Tracking aspect of ads. In a broader context than just Chrome, it varies by platform and ad system, but some ad networks will not collect as much information knowing that they can't target from it. So there may be a marginal privacy advantage from that.
But a very real reason to "opt out" (assuming you don't block trackers outright, which is the vastly preferred privacy solution) is: it may send a signal to the ad networks that you don't consider cross-site / cross-device targeting to be a fair trade-off for viewing the affected pages. In addition, it may even reduce the revenue to the ad networks since they can't sell presumably higher-cost more-targeted ads onto your page views. The signal plus the possibility of reduced revenue may in the long run contribute to a healthier (for users and user privacy) ad ecosystem.
But keep in mind that Blocking is the only way to get a large immediate privacy advantage over ubiquitous Tracking.