A standard standing order of mine: compare and cross-check, as frequently as possible, with any and all tools at one’s disposal. So, for collision-avoidance purposes, I encourage my mate to use the AIS solely for the purposes of target identification and comparing against the radar and the . If all three agree you’ve got a winner. AIS is by far the lowest ranking of the three, and the first to be disregarded if there is any disagreement.
I generally will not ever use AIS, or allow it to be used, as a standalone means for collision avoidance. Radar, radar, radar + all the time. But, never say never. If the radars or ARPAs are all blown out in rain, or fail outright, I’d much rather have the AIS option than not.
It’s like anything else: it’s okay if used carefully and wisely and with restraint, and a full understanding of its limitations. Never trust it too much or let it become a crutch to compensate for weak radar skills or laziness.