A controversial statement to start: Celtic could do with drawing their next game.
My reasoning is as follows: As things stand, Rangers are on 79 points with six games to play - the maximum total they could achieve is 97 points. Celtic are on 91 points, with an insurmountable goal difference. What that means is that if Celtic win their next two days they will have won the league... in every sense but the strictly mathematical. (By which I mean that strictly speaking it's not impossible for Rangers to oerturn it, but it's just not going to happen.)
The upshot of that is that if they win their next two games, Celtic fans will find themselves in a weird twilight zone - do they celebrate the league win when it's not quite done, do they wait for the next game when it's a formality, or (most likely) do they have a mix where some people do one and some the other and it turn into a bit of a mess?
Far cleaner is if they draw the next match, then win two, jump from 95 to 98 points, and put it beyond even strict mathmatical doubt in one step.
(Not that it really matters all that much - the league is long since done. The only remaining questions are just when do they cross the line, and what is their final points tally?)
On the other hand, as far as I can tell, the highest-ever points tally in Scottish football is 106 (though I might be wrong - I haven't checked every single season!). If Celtic win all six of their remaining matches, they could hit 109. Which also provides a compelling reason to keep going!