DC in Miami, explains why Telegram app is snappy fast for me. I notice similar speed improvement with Meta and other big tech apps when I'm on the west coast. I guess latency matters when your app is making tons of requests.
Most of big tech's major data centers are in Loudoun County, VA on the east coast not the west coast. It's centrally located to be great latency for the east coast and OK latency for west coast and Europe. Plus a friendly regulatory environment and lots of existing DCs (AWS us-east-1, Azure East US 1/2)
If you're feeling any better latency on the west coast it's more likely to be placebo than real.
Your experienced latency will be heavily influenced by which DC you hit, in which case we care about the relative traffic loads because you aren't just hitting your closest one all the time.
When I was in Seattle I noticed youtube, facebook and maybe other apps load and run faster. I was on fiber internet at an apartment. Back in Miami I was on Comcast cable but recently got fiber here as well and there was not noticeable improvement. I guess next time I'm in Seattle I will do screen recording to compare.
If you're feeling any better latency on the west coast it's more likely to be placebo than real.