Turkey has taken in 2.7 million Syrians from the brutal war that broke out across its border in 2011, making it host to the largest refugee population in the world.
In the absence of official refugee status – Ankara refers to them as "guests" – integrating into Turkish society and the labour market is a constant struggle.
For Mohammed Nizar Bitar, a Syrian who arrived five years ago, the prospect of citizenship is "excellent news, because we're going to stay here anyway".
"This would seriously improve the living conditions of my compatriots," said Bitar, who owns three restaurants in Istanbul employing dozens of Syrians.
But the announcement has not gone down well with everyone.
As Erdogan announced the decision at the weekend, hailing the "good news", the hashtag #ulkemdeSuriyeliistemiyorum ("I don't want Syrians in my country") trended on Twitter.
Turkey's open-door approach to refugees was initially a source of pride for many Turks, but more and more have come to resent them as a drain on state resources and competitors for jobs.
Offering them citizenship was bound to be unpopular with some of Erdogan's voters. So what is the Turkish strongman playing at?
ARMY OF VOTERS?
Ankara has yet to detail of how the citizenship process would work, from the timeline to eligibility criteria.
But Jean Marcou, a Turkey expert at France's Sciences-Po university, said most refugees are planning to stay in Turkey long-term in any case.
"They have settled, found work and begun to integrate," he told AFP.
"Turkey knows there is nothing else to do but deal with the situation that's been handed to it."
Increasingly, Ankara accepts any resolution to the war will likely leave its foe Bashar al-Assad in power, analysts say – a situation that would leave many refugees unwilling to go home.
With this in mind, Erdogan appears to be calculating how to make the best of the situation.
For Marc Pierini, visiting scholar at Carnegie Europe, Syrians represent a "reservoir of voters" for Erdogan.
"For those who've arrived with just a backpack, Erdogan is a father figure who has given back their dignity," Pierini told AFP, pointing to benefits enjoyed by refugees including ID cards that unlock free healthcare.
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Crucially, grateful Syrian voters could help Erdogan achieve his dream of pushing through constitutional changes to give Turkey a presidential political system.
For that, he needs either a three-fifths majority in parliament to call a referendum on the issue, or a two-thirds majority for direct approval.
His AKP party currently holds just over half the seats.
Citizenship is a "tactical ploy", said Aykan Erdemir, a senior fellow at the Foundation for Defense of Democracies think-tank.
"Erdogan expects a vast majority of Syrian refugees to vote for him," the former lawmaker told AFP.
"This could boost his electoral performance, potentially giving him a super-majority to single-handedly amend the constitution and/or win a referendum."
The policy could also provide an international "image boost" as Ankara tries to build regional clout by repairing damaged friendships with Israel and Russia, according to Marcou.
It could position itself as a friend to refugees at a time when the EU's response its migrant crisis is drawing heavy criticism, he said.
Erdogan has pointed to the economic benefits of welcoming refugees.
"Some of them are very qualified – and if we don't accept them they will leave for Europe, for Britain and Canada," he said Tuesday.
Erdemir also said the refugees offered long-term benefits to the struggling Turkish economy.
"Turkey has long celebrated its young population – however, this 'demographic window of opportunity' is coming to an end as the country is soon to join other ageing societies," he said.
But he stressed that integrating refugees properly would require "adequate education, retraining, and integration programmes".
"Erdogan seems to be unaware of the complexities involved, and risks turning a potential win-win arrangement for Turkey and Syrian refugees into a lose-lose deal for both," Erdemir warned.
And he added that the Turkish president needed to tread carefully.
As seen with the flood of angry tweets, the policy could stir up "anti-refugee sentiment and xenophobic rhetoric", hurting refugees in the long-term, he said.