Sooo, blips and visual sightings are comparable how?
For those with their mind made of pro or con radar, save yourself the time and stop reading.
Given that we all pretty much navigate with GPS plotters, there is very little out there shown on the radar, aside from off-station buoys and daymarks, which is not right where we see it on the chart except where charts are in error (noted before in this thread). This tempts people to boat in low visibility conditions with false confidence. If you are smart enough to clear the channel and stop or just stay home when zero visibility conditions prevail, you can certainly justify not having radar.
OTHER things like unlighted vessels or vessels hidden from sight by rain or fog or smoke are the blips you are looking for, and radar overlaid on electronic charts makes that important task simple - plus those fun times when electronic charts are in error or maybe you just have the wrong chart datum selected.
If it has not already, the day may come when you will be adjudged totally liable if colliding with another vessel in low visibility if you vessel is not equipped with radar. For now, you will get in trouble if you have a radar and do not use in properly resulting in a low viz collision.