I think the best way to address this question of straps or not is from a real expert holster maker. Rob Leahy, the holster maker and proprietor of Simply Rugged states;

"I do not encourage the Hammer Strap for general carry. If you sky dive, fly high G acrobatics or ride motorcycles inside a metal cage,THEN you might need a hammer strap. My holsters are designed and built to retain your pistol when worn on a proper belt without a mechanical latch or strap."

Citation of page: Leather gun holster, concealed carry holster - Simply Rugged Holsters? - Proudly made in the USA
(just below the pictures)

I have three sourdough pancakes, none have the straps. I see no need for them since I gave up motorcycle cage riding weeks ago.