SMS doesn’t handle pictures, videos, gifs, reactions, or group conversations. Things I use all the time. MMS handles some of that, but implementation varies greatly by carrier and device. If you want consistency of that functionality, you have to go with an app. Apple and Google have created replacements for SMS and MMS that could be the next version of “texting” but Apple refuses to let anyone else use theirs (iMessage) and Google has only half opened up theirs (RCS), so those don’t really fix much.
Mostly just freeways. I don’t think it’s heavily enforced. The idea is that cars traveling at drastically different speeds on the same road are more likely to cause an accident. It’s best to drive “the speed of traffic” because that’s what is predictable. Roads should be designed in such a way to make the target speed limit the fastest speed at which most people feel comfortable anyways, rather than just obeying a sign. So a 20mph road should be skinny and not straight. A 70mph highway should be wide and straight. Back to the point, though, in a traffic jam, all the cars are slow and therefore the speed differential is small already and therefore no reason to ticket anyone.