Which Thai Embassy/Thai Consulate (Where) did she apply and receive her DTV Visa from??
From what you have described, it sounds like she received a DTV E–Visa and the PDF File from the Thai Embassy/Thai Consulate is her DTV E–Visa
However, if the actual scenario is that if she received a DTV Visa Sticker inside her passport, then that is very unfortunate and that DTV Visa Sticker was her Thai DTV Visa
of course you can and should prefer to have your LTR issued as a Thai E–Visa by a Thai Embassy/Thai Consulate, rather than an ink Stamp from the LTR/BOI Visa Office in Bangkok, as, for example,
if/when you renew your passport or if it is lost/stolen, then there are more additional procedures/steps to do than if you had a Thai LTR E–Visa from the Thai eVisa website
the only disadvantage of getting a Thai LTR E–Visa from a Thai Embassy/Thai Consulate via the Thai eVisa website as a PDF would be that the LTR E–Visa Fee paid to the Thai Embassy/Thai Consulate outside Thailand would be more than 50,000.- Thai Baht paid in Cash at the LTR/BOI Visa Office in Bangkok