So far I have few L2VPN circuits working correctly and the LSPs are unidirectional. Do you think is mandatory to enable the feature "Corouted Bidirectional LSP" into MPLS protocol section?
Not mandatory. AFAIK, JUNOS imposes only 1 mandatory requirement for L2circuits - the tailend IP/32 must be present in the inet.3 table as exact /32 active route. Which means a given L2circuit can run over RSVP transport in one direction, and on LDP or Segment Routing transport in another direction.
I also haven't found the reference you mentioned in my edition, but I think the whole discussion about bidirectional co-routed LSPs is driven by MPLS-TP (Transport Profile). As far as I can remember, bidirectional LSPs are mandatory for GMPLS and MPLS-TP is kind of a superset of it. So, im my opinion these types of LSPs only make sense if you want to use the network for Layer-1 transport over packet networks.
For standard Layer-2 VPN/ Layer-3 VPNs use cases, I haven't seen a single co-route bidriectional LSP implementation at all.