The risk of explosion is rare, should the safety seals fail it's likely that a small hole starts venting the gas which immediately catches fire on exposure to the air which may result in popping sounds. YouTube lithium poly batteries.
Lithium ion is considered fairly stable which is why it's allowed on airplanes in laptop batteries. Although it's probably because there all encased in a hard, well sealed chamber in the event that they fail.
The reason you use lithium batteries is because they give very high current with small form factors.
If you have no need for high current or a small battery sizing, the risks probably aren't worth it.
What you end up using doesn't really matter as long as they can provide the voltage/current required and you can find a charger for that type and happy with the form factor to risk ratio.