It's possible that Bournemouth will win Chelsea because of their consistency in their previous matches. Chelsea's performance is not stable and unpredictable which makes it impossible for you to rely on them. Bournemouth is in their best form and shouldn't be underestimated because they don't have a big name. Chelsea needs to improve their performance if they don't want to be bonus point for Bournemouth.
Chelsea are experiencing a decline in performance lately, where in the previous 4 matches they have not won even once, so it is clear that the match when hosting Bournemouth later will not be an easy match for them and also considering Bournemouth are in a positive phase this season so I think even though Chelsea chances of winning are higher, it does not rule out the possibility of losing again.
Thus the safest bet in their match is BTTS.
The match between Bournemouth and Chelsea is very important for this bet, but if we feel doubtful it is better not to take a position with doubt, there is always regret when it ends in failure, unless we are ready for defeat, use money wisely here.
I also see Chelsea who have experienced a decline in several weeks, they have a bad match and only get 1 win, two losses and two draws in their last five matches, this shows that Chelsea is not doing well at the moment, and that is also what makes us doubt the results of the match against Bournemouth, if only Chelsea had not lost to Ipswich and Crystal Palace or lost to the team above them, maybe we would still be very confident with the victory that could be taken against Bournemouth.