If someone is spending their own money, then going with a vendor that feels the most competent is going to deliver a better overall result than lowest-bid. But if someone is spending other people's money, then too much subjective freedom in choosing the vendor greatly simplifies corruption, and it's not obvious whether the end results will be better.
What lowest-bid tenders critically need is competent, motivated people working for the government writing the Request for Proposals. People who know the field, know the risks and complexities, and know the "tricks" used to underbid and overrun. People who write tenders that push an appropriate amount of risk and liability to the vendors - not letting themselves to be taken advantage of, but also not adding too many penalties that make vendors pad their estimates just in case and reach for expensive lawsuits if something happens.
If you have that, then there is a good chance that the bids will work out for all parties. But if not, then shady vendors will steamroll over the customer.