New guy with a question

Ofcourse, but assuming that the springbars on such a recent model Speedmaster are OEM Omega, you should be fine.

Using these bars on the C&B supreme NATO
https://www.crownandbuckle.com/spring-bars-20mm.html

There is also the look, personal preference and all, but I think a nice watch like the speedy looks more business and less flash on a quality NATO strap .

I find NATO-type straps to be extremely comfortable. So besides the protection they offer from popped spring bars, the comfort factor is a huge plus.

I was standing on my front deck, about 10 feet above my driveway. Smoking a cigar, watching the ducks across the street in the lake, when I bumped my wrist on a support post. Right on the upper spring bar. Bent it enough to pop it out. But the lower spring bar held the watch on the strap, averting a disaster that would have entailed wailing, tears, and gnashing of teeth. Now a metal bracelet might have offered the protection to keep a knock like that from popping the spring bar, so who knows if the NATO actually saved the day? But it did it's job and kept the watch on my wrist, preventing a 10 foot fall onto asphalt. My Speedy would have been falling for almost a full second before impact, traveling at just over 8m/sec, and would have been carrying a little over 4.5 joules of energy. Ouch! Or it would have been an ouch.