Listen to season 4 of Michael Lewis' podcast. He covers the downsides in detail.

https://www.pushkin.fm/podcasts/against-the-rules

I think this is the ep that gets into the most detail, but I haven't read the transcript.

https://www.pushkin.fm/podcasts/against-the-rules/vegas-spor...

IIRC, if you're too professional or too lucky, the betting apps will restrict you and then lock you out. They only want the dumb money playing.