What is this "more important thing" you speak of which is apparently more important than securing your career
If he rushed his decision to get into franchising, theres no guarantee that he will be able to perform like this, especially with new teammates. And theres literally no downside for him to turn down that offer, its probably increase it on the future because now he is way better than he was a year ago. And more ready too to compete on highest level. Its not a dumb decision at all.
Also he is still young, the game also very young, he isnt wasted any year at all. He have plenty bright chance in the future with how good he is.
Sticking with the core increases stock value in itself to show that the player is not just chasing money and has passion. The Guard is also like a franchise team smurfing in t2 right now, his taking the gamble is completely well placed since now that if Guard has made it to franchising he got what he wanted and if Guard doesn't: he gets picked up and replaced the people on current franchise rosters. Dephhh was seen as a top 2 NA IGL but now with the whole Sentinels situation he no longer plays and I doubt he will ever get another offer from franchising unless he grinds T2. Players on many franchise rosters are at such risk of being kicked out of franchising then joining a fresh t2 project and never making it back into the league(Look at Xand, we'll see these examples in 2024).
Franchising is Do or Die and sure you secured money but if you are in a fucked project, you don't want to end up like yay whose stock was at an all-time high now shadowed by his teams poor performance(DSG).