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.
Chelsea started this season well amd there was a kind of assurance that they will make a difference this season and at the end of the a they are not making any difference just that they seems to be better than even Manchester United and in there previous matches they struggled to be able to even win one match and they won't be able to move forward compare to when the season started that is the problem they start what they can not finish and Chelsea have changed to many coaches just to improve.
And in there last five games Bournemouth looks more stable than Chelsea, the competition is no longer in favour of Chelsea and there is a lot for them to do, and playing against won't go as easy as they think, and I don't know what you must have seen to say that Chelsea's chances are higher the thing is that you don't underestimate all this clubs.
There is still hope doh but we can not underestimate the both of them because Chelsea last game they won 5:0 but that was because the club they are playing against is weak, so there is no difference the only thing that matters is the mindset.