For simple “clocking” yourself, sure, it’s fine.
I have a couple of Sports Radar Tracer SRA3000 Sport Radar Gun w/ Trigger / Continuous / Average Modes, Stats. It’s the gun just to the bottom right of the web page that you listed here. I’ve found that plug, the Tracer, to be just as good as the more expensive guns, and they can be put into suit cases, equipment bags and other carry bags without worrying about damage. But, this does not mean that they can be abused.
For park and rec use, these things are ok. On the other hand, they are directional sensitive. In other words, it’s best to be in-line with the ball coming in, or, even behind the pitcher gunning the ball going to the catcher. Either way, they’re fun, and fairly cheap for what you’re getting - that is if you have a $100 bucks you can part with.