Spammers can spam in altcoin section a lot without the tension of post getting deleted. Most of the signature spammers post in altcoin section only. Bitcoin boards are moderated much heavily than altcoin boards.
Most bitcoin-related sections are moderated more heavily than the altcoin section, but spammers and shitposters are still very much attracted to Bitcoin Discussion last time I checked--and that's got to be a hard section to moderate, because of the sheer number of posts getting made on a daily basis.
And you're right, the reason for OP's observations is signature campaign spammers/bounty hunters. Period. A lot of them don't know much about crypto, so they post generic posts in the altcoin section, which is the most relevant section to whatever altcoin/token bounty they're in.
There can be many reasons:
- More Altcoins coming up everyday
- More users getting attracted to quick money
- DeFi Trend
It's the second reason listed above that's the primary one. I don't know how many altcoin section posters are wearing advertising in their signature, but if I had to guess it would be over 90%. There might be some hype about DeFi sparking new threads, but most of the posts made within those threads are likely garbage shitposts made by bounty hunters. And I don't think the first reason listed above has anything to do with it.