Getting paid to send messages in a group is fine, but the major issue here is that it will likely lead to spam from those who are trying or will be trying so hard to get picked by the automatic selection bot.
And another important thing I will also like to discuss on the matter of valuable messages, valuable messages come in different ways and sometimes, even a sentence with 5 words alone can be very valuable.
So, I don't know the casino's definition of valuation messages but all the same, I am happy that something positive is happening with this platform after almost 2 years of issues.
I don't think they care. This is a rather common method of promoting a telegram channel. They get random people to spam their page and subscribe to grow their numbers and increase their views. This is why so many telegram channels have high number of members and very low number of post views (eg. 100k members, 1k views per post on average).