Before going out for a ride I shall attach my gazillion candlepower flashing front light, flashing back light, wheel reflectors, flexy-pole bike flag, air canister boat horn, and pool noodle. I then put on my reflective vest, mirror, helmet camera, pepper spray and revolver.
If these various accessories make you feel safer, then use them by all means. (Well, except for those super bright white blinking lights.) But until I see any studies showing that these various accoutrements make any significant difference in rider safety I'll limit my safety equipment to a helmet, also lights when it's dark, foggy, or raining. They've served me well for the last 50 years.
I've had my share of nasty experiences with cars, four to be exact, but no pool noodle or flashing lights would have helped in any of those instances. Two of them were drivers who assumed that because I was on a bicycle I must be slow, so after passing me made right turns in front of me, running me up the curb each time. One was an oncoming driver who chose to make a U-turn in front of me: Her apology/excuse was "I thought I had plenty of time." The fourth was a driver on the wrong side of the road on a blind turn.
As for the "take the full lane when descending" nonsense advocated by the writer of the linked article, If you can't keep from riding off the shoulder when taking only the outside foot or two of the lane, then you shouldn't be riding your bicycle on hilly terrain. Be as polite to the drivers as you expect them to be to you.
Brent