I've actually touched on this, in part, years ago: here, but that can probably be expanded on by someone. My understanding of the matter was that religion was a major part of the national identity for many of the ethnic groups in the Balkans, so when the Turks conquered the region, the Serbs and Greeks and so on kept that up to preserve their identity and culture.

The Albanians were not so interested in religion for that aspect, and instead saw Islam as a means to preserve their traditional way of life. They heavily relied on the use of weapons to keep that going, which the Turks only allowed Muslims to keep, so it was logical for the Albanians to adopt Islam, if only in name, in order to keep and use weapons.

I'll also note two minor points as well: Albanian was not a literary language, so unlike the aforementioned Serbs and Greeks, they had no use for religion to preserve their texts or stories. And while Albanians largely converted to Islam, it was really just for show, and many also adhered to either Catholic or Orthodox Christianity, to the point that many Albanians had both a Christian and Muslim name, but didn't really care for either. Their primary goal was to preserve Albanian culture, by whatever means necessary.