It's better to apply for only business cards (as much as you can) if you're interested in applying for Chase cards. Chase doesn't approve for most cards (and perhaps someday in the future for any card?) if you have 5 or more bank credit cards showing on your credit report with an "opened on" date in the past 24 months. But business cards from most banks (Discover and Cap One being the main exceptions) don't appear on EQ/EX/TU credit reports, and thus are not counted by Chase for that 5/24 count. So if you apply for virtually nothing other than business cards for two years, you can get back into applying for Chase cards.
Also,
the BofA 2/3/4 anti-churning rule applies only to personal cards. (Though it's not clear whether you can churn business cards any faster than that.)
And there are different pitfalls you have to avoid with personal vs business cards. With personal cards, if you're approved with a creidit limit less than $5000, that's a "fate worse than death", because it means you still get a card but you don't get the 30k bonus. There is no such issue with the business card. But OTOH, the business card may be harder to get approved without jumping through hoops such as opening a $1500 Certificate of Deposit or supplying hard-to-supply business documents.
So there is no simple answer about which is better or easier. There are a lot of factors to consider, and each person may come to a different personal decision based on those factors.
The main fact is: It's hard to churn Alaska cards "quickly" any more. You can only churn them fairly "slowly".
Also, Alaksa airlines itself may be shutting down some accounts which have no other miles coming in except from BofA AS card signups. So i suggest if you're going to churn AS cards, that you also earn AS miles some other way (AS dining program, AS shopping mall, hotel stays or car rentals, whatever, just so there's "variety" clearly showing in your AS account). If you regularly fly AS anyway (and credit AS when you do), that shouldn't need to be a concern.