Hi guys - seeking advice about the decompression mechanism.

Im having some major work done on my Tenere such as new piston and rings etc etc and the mechanic doing this work notified me about that the decompression mechanism was disconnected on my bike.
I wasnt aware of this at all and to be honest I dont know much about it at all. The only issue I have had with the bike is high fuel comsumption and a dead ECU a while ago. Never had starting problems related to the decomp mechanism.
So the question is should we connect back the decomp mechanism or leave it like it is?

Thanks in advance for help and advice.

__________________
Suzuki AC 50 -78 owned from 83 to 84
Kawasaki Kh 100 Es 81 owned from 84 to 86
Honda Transalp Xlv 600 -97 owned from 01 to 05
Honda Nx 650 Dominator -98 owned from 07 to 10
Triumph Tiger 955 i -01 owned from 10 to 13
Yamaha XT660Z Tenere ABS -11 owned from 2013 and present bike.
Honda Crf250L -12 my bike in Thailand.