I just want to share my experience on whether or not "sandbagging" in Pool 2 to delay one's entry into Pool 3 is worthwhile. There have been some reputable Snap streamers on Youtube and Twitch, the majority of whom started in the beta and have full accounts already, who have advised that there's little benefit to delaying Pool 3 entry, but at least in my case I'm glad I did it.
I started playing Snap on October 25, with about 2 weeks left in the Miles Morales season pass. As MM season was ending and Wakanda season was starting, many players were hitting Pool 3 and suffering the Pool 3 "wall", and people started to advise staying in Pool 2 longer to stockpile credits before hitting Pool 3. Since I was a few weeks behind those players, I calculated that I would be able to stockpile and reach the credit cap right around the end of Wakanda season, so that was my target date.
In Pool 2, I started sitting on around CL 400 and stockpiling credits as soon as I had pulled all of the "essential" Pool 2 characters - mainly Killmonger, Shang Chi, Scorpion and Storm. Not only did I stockpile credits, I also stockpiled my credits and boosters from CL rewards, Season rewards, and Ranking rewards. Finally, I stockpiled my Frame breaks so that I had around 70 frame breaks in reserve. As I hit the credit cap, I would spend credits to slowly raise my CL towards 474. Some unexpected things happened along the way: I went over the road and missed about a week of daily and weekly mission rewards, and the last patch raised the credit cap to 10,000. But still, by Sunday evening's shop refresh I was sitting on CL 443 with 9800 credits plus all my reward credits still untapped. It was time to break the bank, collect all my rewards, and dive into Pool 3.