However on a previous aircraft type, the Omni Bearing Selector (OBS or QDM selector) was next to the Heading and Speed selectors and it was very easy to move the wrong one. The last chance we had to correct the error was by 350' else the Auto Land system would miscalculate the amount of Align to apply during the flare.
I think the "350 feet" rule is a hang over from the old days and needs to be updated with the modern equipment in use.
I don’t think Airbus intended to adopt this procedure based on how other aircraft used to be . Prior to the 320 family was the A310 whose MCP (FCU) was again not the same as a typical Boeing (the CRS selector on the 310 was on the pedestal so you couldn’t accidentally change the OBS if you were changing the heading bug) . One thing you will definitely have seen is that Airbus in all likelihood is obsessed with avoiding doing things and naming things the same way Boeing does .
The 350ft check remains a mystery